UC-NRLF 


CARCINOMA  OF  THE  THYROID  IN  THE  SALMONOID 

FISHES  :  :  :  By  Harvey  R.  Gaylord  and  Miilard  C.  Marsh 

Publications    from    STATE    INSTITUTE    FOR   THE   STUDY   OF    MALIGNANT   DISEASE 


Serial  No.  99 


Issued  April  22,   1914 


WASHINGTON 


GOVERNMENT  PRINTING  OFFICE 


CARCINOMA  OF  THE  THYROID  IN  THE  SALMONOID 

FISHES  :  :  :  By  Harvey  R.  Gayloid  and  Millard  C.  Marsh 

Publications    from    STATE   INSTITUTE   FOR   THE  STUDY  OF   MALIGNANT   DISEASE 


Serial  No.  99 


Issued  April  22,  1914 


WASHINGTON 


GOVERNMKNT  PRINTING  OFFICE 


1914 


S 
(L3C  3 


BIOLOGY 


CARCINOMA  OF  THE  THYROID  IN  THE  SALMONOID  FISHES 

An  investigation  and  experimental  study  conducted  jointly  by  the 
Gratwick  Laboratory  of  the  State  Institute  for  the  Study  of  Malignant 
Disease,  Buffalo,  N.  Y.,  and  the  United  States  Bureau  of  Fisheries 


By  Harvey  R.  Gaylord,  M.  D. 

Director,  State  Institute  for  the  Study  of  Malignant  Disease,  Buffalo,  N .  Y. 

AND 

Millard  C.  Marsh 

Biologist,  State  Institute  for  the  Study  of  Malignant  Disease,  formerly 
Scientific  Assistant,  United  States  Bureau  of  Fisheries 

WITH  THE  COLLABORATION  OF 

Frederick  C.  Busch,  M.  D.,  Internist,  AND  Burton  T.  Simpson,  M.  D.,  Pathologist 

State  Institute  for  the  Study  of  Malignant  Disease 


363 


CONTENTS. 
j* 

Introduction 367 

History  of  the  present  investigation 367 

History  of  the  disease 369 

Normal  thyroid  in  salmonoids 373 

Embryology 374 

Gross  anatomy  and  distribution  in  the  adult  brook  trout 376 

Anomalous  deposits  of  thyroid 377 

Histology 378 

Simple  hyperplasia  and  colloid  goiter  in  wild  and  domesticated  fish 379 

Pathologic  anatomy 382 

Gross  anatomy 382 

Earliest  macroscopic  evidence 382 

Visible  tumors 383 

Branchial  junction 383 

Floor  of  mouth 384 

Pit  tumors 384 

Histology 397 

Early  stage 397 

Red- floor  stage 398 

Visible-tumor  stage — Structural  types 399 

Infiltration 400 

Bone  and  cartilage;  vessel  wall;  muscle;  skin 401-402 

Other  observations 402 

Implantations  and  metastases 404 

Comparative  pathology 407 

Occurrence  of  the  disease  under  wild  conditions 411 

Occurrence  and  course  of  the  disease  under  domestication 413 

Distribution  of  the  disease  in  United  States  hatcheries 413 

Names  of  species  and  hybrids 414 

Geological  formation  at  fish  hatcheries 415 

Chemistry  of  the  water  supplies 419 

Dissolved  oxygen 420 

Endemic  occurrence 424 

Caledonia  hatchery,  New  York 424 

Craig  Brook  station:  Conditions  at  the  beginning  of  the  investigation 425 

Craig  Brook  station:  Conditions  during  three  years 428 

Lake  Auburn  hatchery,  Maine 435 

Private  hatchery  in  the  State  of  Washington 436 

Epidemic  occurrence 436 

365 


366  CONTENTS. 

Occurrence  and  course  of  the  disease  under  domestication — Continued.  Page. 

Hybridization 441 

Clinical  course 441 

Morbidity  and  mortality 441 

Hemoglobin  estimations 447 

Spontaneous  recovery. . . . .' 448 

Immunity 450 

Experimental  production  of  the  disease 453 

Trout  tumor  material  in  standing  water 453 

Feeding  trout  thyroid  tumor 453 

Feeding  human  cancer  liver 453 

Closed  circulation 453 

Transplantation  and  inoculation  experiments 454 

Experimental  induction  of  carcinoma 457 

Chemotherapy — Effect  of  iodine,  mercury,  and  arsenic  upon  carcinoma  of  the  thyroid 463 

Transmission  of  thyroid  disease  to  mammals 485 

Dogs 485 

Rats 490 

Possible  carriers 495 

Summary,  in  English 502 

In  German 507 

In  French 513 

Conclusions,  in  English 506 

In  German 511 

In  French 516 

Bibliography 519 

Plates 524 


CARCINOMA  OF  THE  THYROID  IN  THE  SALMONOID  FISHES. 

* 

By  HARVEY  R.  GAYLORD,  M.  D.,  and  MILLARD  C.  MARSH 

WITH   THE  COLLABORATION   OP 

FREDERICK  C.  BUSCH,  M.  D.,  and  BURTON  T.  SIMPSON,  M.  D. 

> 

INTRODUCTION. 

HISTORY  OF  THE  PRESENT  INVESTIGATION. 

In  1907,  by  the  natural  trend  of  the  general  investigation  into  cancer  which  was 
being  conducted  by  the  State  of  New  York  through  the  medium  of  the  Gratwick  Labo- 
ratory, now  a  part  of  the  State  Institute  for  the  Study  of  Malignant  Disease,  that 
institution  became  interested  in  the  possible  distribution  of  cancer  and  allied  affections 
in  fish.  Through  publications  of  Plehn  and  Pick  the  attention  of  cancer  investigators 
was  attracted  to  a  disease  known  as  carcinoma  of  the  thyroid  in  the  Salmonidae.  The 
disease  had  been  described  in  the  literature  under  various  names  and  was  known  to  fish 
culture  as  "gill  disease,"  "  throat  tumor,"  etc.  The  work  of  Marianne  Plehn  had  served 
to  establish  the  nature  of  the  disease  as  cancer  or  carcinoma  of  the  thyroid,  intimately 
associated  with  enlargement  of  that  organ  of  a  more  simple  nature  which  might  be 
considered  goiter. 

In  1907  the  director  of  the  Gratwick  Laboratory  took  occasion  to  visit  one  of  the 
hatcheries  in  New  York  for  the  purpose  of  inquiring  into  the  prevalence  of  this  disease 
in  the  hatcheries  of  the  State.  He  learned  that  one  or  two  fish  with  tumors  at  the 
junction  of  the  gills  had  been  found  and  in  the  spring  of  1908  a  report  came  from  this 
hatchery  that  an  epidemic  was  in  progress,  and  an  examination  made  on  the  spot 
revealed  the  presence  of  visible  tumors  in  some  700  fish.  Attempts  were  made  to  study 
the  conditions  under  which  the  disease  developed  in  this  hatchery,  and  observations 
were  carried  through  the  summer  of  1908.  Attention  was  called  to  the  existence  of  the 
disease  in  two  other  hatcheries  in  the  State  of  New  York,  and  at  the  conclusion  of  the 
summer's  work  it  became  apparent  that  the  great  extent  of  the  disease,  the  existence 
of  which  in  other  States  had  been  reported  to  us,  was  such  that  a  comprehensive  inves- 
tigation could  probably  be  successfully  accomplished  only  in  cooperation  with  the 
United  States  Bureau  of  Fisheries. 

367 


368  BULLETIN  OF  THE   BUREAU   OF   FISHERIES. 

For  this  reason,  in  February,  1909,  the  results  obtained  and  the  importance  of  the 
subject  were  laid  before  President  Roosevelt,  who  decided  that  a  joint  investigation 
between  the  Gratwick  Laboratory  and  the  Bureau  of  Fisheries  should  be  undertaken. 
The  Commissioner  of  Fisheries,  Hon.  George  M.  Bowers,  detailed  Mr.  Millard  C.  Marsh 
as  the  representative  of  the  Biireau  to  cooperate  with  the  State.  Facilities  were  at  once 
afforded  for  a  detailed  investigation  at  one  of  the  Government  fish  hatcheries  where  the 
disease  was  endemic. 

The  first  summer's  work  was  carried  out  by  Dr.  Gaylord  at  this  Government 
hatchery.  In  the  winter  of  1909-10  Mr.  Marsh,  working  at  the  Gratwick  Laboratory 
in  Buffalo,  in  conjunction  with  Dr.  Gaylord,  carried  out  a  series  of  experiments  on 
feeding,  crowding,  vitiation  of  water,  etc.  The  summer  of  1910  was  again  spent  by 
Dr.  Gaylord  and  Mr.  Marsh  at  the  Government  hatchery  in  question.  The  winter  of 
1910-11  Mr.  Marsh  continued  the  work  in  Buffalo.  In  July,  1911,  Mr.  Marsh  was 
detailed  for  service  in  Alaska  and  Dr.  Frederick  C.  Busch,  of  the  State  Institute  for  the 
Study  of  Malignant  Disease,  took  up  his  part  of  the  work.  In  the  pathologic  histologic 
part  of  the  work  Dr.  Burton  T.  Simpson  contributed  largely,  having  studied  many 
hundred  sections  and  recorded  important  facts.  The  experimentation  at  the  Govern- 
ment hatchery  has  been  conducted  to  a  point  where  it  is  now  possible  to  make  the  first 
report  on  the  studies  thus  far  conducted  into  this  disease. 

In  this  report  we  have  attempted  to  determine  the  nature  of  this  affection,  to  present 
a  well-defined  picture  of  the  disease  as  it  occurs  in  hatcheries  under  conditions  of 
practical  fish  culture,  to  determine  as  nearly  as  possible  the  factors  which  predispose  to 
the  development  of  the  disease,  and  to  present  certain  conclusions  regarding  its  nature. 
Identification  of  the  agent  which  causes  this  disease  we  have  left  for  future  investigation. 
How  important  to  fish  culture  and  how  significant  to  cancer  research  future  studies  in 
the  more  sharply  defined  field  to  which  this  report  is  an  introduction  will  prove,  may  be 
easily  seen  from  the  significant  facts  thus  far  adduced. 

In  our  investigations  and  in  the  preparation  of  this  report  we  have  had  assistance 
from  many  persons  to  whom  we  wish  here  to  acknowledge  our  indebtedness.  The  joint 
investigation  was  begun  during  the  incumbency  of  Hon.  George  M.  Bowers  as  Commis- 
sioner of  Fisheries,  and  the  resources  and  facilities  of  the  Bureau  were  freely  used  by  him 
in  furtherance  of  the  mutual  undertaking.  Likewise,  Dr.  Hugh  M.  Smith,  who  as 
Deputy  Commissioner  interested  himself  keenly  in  the  encouragement  of  the  work,  has 
since  his  recent  appointment  to  the  commissionership  continued  in  every  ..way  to  give 
indispensable  support  and  cooperation.  The  members  of  the  fish-cultural  and  scientific 
staffs  of  the  Bureau  in  Washington,  and  superintendents  and  employees  of  stations, 
have  given  much  time  and  effort  in  various  ways.  Of  the  latter,  Mr.  C.  G.  Atkins, 
superintendent  of  Craig  Brook  station,  has  been  our  chief  dependence. 

The  Commissioner  of  Forest,  Fish,  and  Game  of  the  State  of  New  York,  Mr.  James 
S.  Whipple,  and  the  State  Fish  Culturist,  Dr.  T.  H.  Bean,  have  furnished  valuable 
assistance  by  placing  at  our  disposal  facilities  and  material  at  certain  of  the  State  hatch- 
eries. The  superintendents  and  employees  at  the  hatcheries  at  Bath,  Caledonia,  and  Cold 
Spring  Harbor  gave  much  direct  assistance. 


CARCINOMA   OF  THE   THYROID   IN   SAUMONOID   FISHES.  369 

The  excellent  plates  in  color  and  most  of  the  other  drawings  are  the  work  of  Miss 
E.  S.  Carrington,  of  Louisville,  Ky. 

Dr.  F.  W.  Baeslack,  formerly  of  the  Gratwick  Laboratory,  autopsied  a  portion  of 
the  tumor-fish  material.  Of  the  present  force  of  the  laboratory  the  work  of  Mr.  Damon 
Averill  deserves  special  mention.  He  has  had  to  do  with  the  fish  material  from  the 
beginning  of  the  investigation,  has  done  a  part  of  the  histological  work  and  all  the 
extensive  photography  involved;  to  the  photomicrographs  particularly,  on  which  the 
value  of  this  report  largely  depends,  he  has  devoted  much  pains  and  skill. 

Miss  C.  A.  Maclay,  secretary  of  the  State  Institute,  has  had  charge  of  many  details 
concerned  in  the  investigation,  has  prepared  much  of  the  manuscript  for  the  printer, 
and  taken  part  in  the  proof  reading. 

The  translations  of  the  summary  and  conclusions  into  German  and  French  we  owe  to 
the  skill  of  Dr.  Max  Breuer  and  Dr.  Charles  van  Bergen,  both  of  Buffalo. 

HISTORY  OF  THE  DISEASE. 

The  existence  of  this  disease  was  first  noted  in  1883  by  a  German  investigator, 
R.  Bonnet,  who  published  in  the  Bavarian  Fisheries  Journal  the  description  of  a  peculiar 
epidemic  occurring  among  the  lake  trout  (Trutta  lacustris)  at  the  fish  hatchery  in  Torbole 
on  the  Gardasee,  and,  between  the  middle  of  February  and  the  end  of  June,  killing  no 
less  than  3,000  fish.  All  of  these  fish  had  tumors  at  the  junction  of  the  gills. 

Bonnet  did  not  recognize  that  this  disease  was  cancerous  in  its  nature.  The  first 
to  recognize  the  tumor  as  carcinoma  was  Scott  (1891).  The  full  text  of  his  "  Note  on  the 
Occurrence  of  Cancer  in  Fish"  is  as  follows: 

The  fish  afflicted  with  this  disease  were  all  specimens  of  the  American  brook  trout  (Salmo  fontinalis) 
kept  in  confinement  in  one  of  the  ponds  at  Opoho  belonging  to  the  Dunedin  Acclimatization  Society. 
Males  and  females  were  alike  affected  and  the  diseased  fish  never  recovered.  Through  the  kindness 
of  Mr.  Deans,  the  manager,  I  was  able  to  examine  several  specimens  showing  the  disease  in  various 
stages  of  advancement,  and  the  following  is  a  short  account  of  the  naked-eye  and  microscopic  appear- 
ances of  the  growth. 

In  the  earliest  stages  the  ventral  wall  of  the  pharynx  in  the  middle  line,  a  short  distance  behind 
the  tongue,  is  seen  to  be  somewhat  roughened  and  raised  in  low  irregular  swellings.  At  this  stage 
nothing  is  to  be  seen  unless  the  mouth  is  opened  widely.  As  the  tumor  grows,  however,  not  only  does 
it  involve  more  and  more  of  the  pharyngeal  floor,  spreading  also  to  a  slight  extent  laterally,  and  involving 
the  ventral  ends  of  the  gill  arches,  but  it  ultimately  shows  itself  externally  as  a  rounded  pink  lump 
on  the  isthmus  in  the  angle  between  the  diverging  branchiostegal  rays. 

A  microscopic  section  of  the  tumor  shows  all  the  stages  in  the  development  of  a  carcinomatous 
growth.  In  parts  a  purely  glandular  structure  is  seen — the  glands,  apparently,  of  the  acinotubular 
type.  Elsewhere,  owing  to  the  proliferation  of  the  cells,  the  gland  acini  have  become  distended  and 
irregular  in  form  (adenoma  stage),  while  in  large  areas  these  overdistended  acini  have  burst,  as  it 
were,  and  the  liberated  cells,  making  their  way  into  the  stroma,  infiltrate  it,  and  all  gland  structure  is 
lost  (carcinoma  stage). 

Of  the  two  figures  which  accompany  this  note,  the  first  (Fig.  i)  shows  the  floor  of  the  mouth  and 
pharynx,  as  seen  from  above,  of  a  fish  suffering  from  the  disease.  The  nodular  character  of  the  tumor 
is  clearly  seen.  The  second  shows  a  small  portion  of  a  section  as  seen  under  the  microscope.  A  distended 
acinus  is  seen  liberating  a  stream  of  cells  into  the  gland  stroma  (Fig.  2). 


370  BULLETIN   OF  THE   BUREAU   OF   FISHERIES. 

The  occurrence  of  cancer  in  the  lower  animals  has  been  frequently  noted  of  late  years,  and  it  is  by 
no  means  so  rare  among  them  as  it  was  at  one  time  thought  to  be.  I  have,  however,  been  unable  to 
find  any  mention  of  it  having  been  noted  in  fish. 

A  report  on  this  disease  in  trout  appeared  in  1 902  in  the  General  Fisheries  Magazine 
(German),  by  Marianne  Plehn,  who  recognized  it  as  a  disease  of  the  thyroid  gland. 
L>  Pick  reported  fully  on  the  subject  in  a  paper  entitled  "Carcinoma  of  the  Thyroid  in 
the  Salmonidae,"  describing  10  fish  affected  with  the  disease,  which,  in  agreement  with 
all  other  authorities,  he  concludes,  is  genuine  cancer.  He  refers  especially  to  the 
epidemics  of  the  disease,  descriptions  of  which  are  found  below. 

In  the  reports  of  the  New  Zealand  Department  of  Agriculture,  Division  of  Veterinary 
Science,  1901-2,  is  a  report  by  Gilruth  entitled  "Epithelioma  Affecting  the  Branchial 
Arches  of  Salmon  and  Trout."  Gilruth  describes  a  specimen,  a  5-year-old  salmon  (Salmo 
salar)  from  the  Clinton  ponds,  which  had  a  growth  on  the  third  branchial  arch  and  "its 
gill  ray."  It  was  the  first  specimen  which  had  been  found  there.  His  description  is  as 
follows : 

Macroscopical  examination. — Growth  appeared  about  the  size  of  a  marble,  situated  on  the  center  of 
the  third  branchial  arch,  affecting  laterally  the  first  and  third  and  implicating  the  branchiae.  The 
gill  cleft  was  distended,  but  until  forcibly  opened  the  tumor  was  not  visible. 

Later  he  received  three  rainbow  trout  (Salmo  irideus). 

In  each  specimen  the  tumor  was  about  the  size  of  a  large  walnut  projecting  on  both  sides  of  the  gill 
cleft.  (Fig.  3.)  Each  tumor  appeared  to  have  started  at  the  apex  of  the  second  branchial  arch,  about 
the  base  of  the  branchiae,  which  they  had  implicated  almost  to  their  terminal  points,  only  leaving  a 
faint  fringe  of  what  were  the  branchiae.  The  first  and  second  arches,  with  their  branchiae,  were  also 
affected.  The  growth  did  not  affect  the  apex  of  the  the  arch  externally,  but  passed  on  the  internal 
surface  through  to  both  sides.  The  external  surface  of  the  tumor  was  faintly  pink.  On  section  the 
tumor  was  found  to  be  homogeneous,  pale  in  color,  and  soft  in  consistency. 

Microscopical  examination. — Fibrous  capsule,  covered  by  several  layers  of  squamous  epithelium, 
from  which  the  fine  fibers  forming  branching  and  anastomosing  trabeculse  pass  inward,  inclosing  more 
or  less  irregular  alveoli.  These  alveoli  are  lined  by  an  irregularly  disposed  layer  of  columnar  cells,  the 
center  of  each  alveolus  being  filled  with  cubical  cells  more  or  less  degenerated.  The  smaller  alveoli 
are  lined  with  columnar  or  cubical  cells,  and  have  the  appearance  of  tubules  cut  transversely,  the 
central  area  only  containing  one  or  two  degenerated  cells.  Blood  vessels  with  thin  walls  and  wide 
lumina  are  found  traversing  the  fibrous  capsule  and  the  fibrillar  network  within.  Frequently  hemor- 
rhage is  met  with  where  the  slender  walls  of  the  blood  vessels  have  ruptured.  In  many  portions  of  the 
tumor  the  branching  fibrillae  with  columnar  cells  on  either  side  show  an  appearance  recalling  somewhat 
the  fronds  of  the  common  fern.  Taking  into  consideration  the  histology  of  the  branchiae  with  the  above 
description,  it  would  appear  that  the  only  pathological  classification,  at  least  from  the  mammalian 
standpoint,  which  this  would  come  under,  is  epithelioma  (as  distinguished  from  carcinoma). 

Gilruth  gives  a  letter  from  L.  F.  Ayson,  Chief  Inspector  of  Fisheries,  New  Zealand, 
who  states: 

This  gill  disease  was  first  noticed  there  [Masterton  hatchery]  among  the  American  brook  trout 
(Salvelinus  foniinalis)  in  1890,  when  three  diseased  fish  were  taken  out  that  spawning  season.  The 
disease  was  peculiar  to  this  species  until  the  rainbow  trout  (Salmo  irideus)  were  introduced,  among 
which  it  made  its  appearance  when  they  were  over  3  years  old.  I  have  never  found  any  of  the 
brown  trout  (S.fario)  affected,  but  took  out  three  diseased  fish  from  a  thousand  3  and  4  year  old  Loch 


CARCINOMA  OF  THE  THYROID  IN   SALMONOID  FISHES.  371 

Leven  (S.  levenensis)  during  the  spawning  season  of  1896.  In  1898  about  2  per  cent  of  the  American 
brook  trout  over  3  years  old  would  be  affected  and  about  i  per  cent  of  the  rainbow  trout  over  that  age. 
I  have  no  record  of  ever  finding  any  diseased  fish  under  3  years  old. 

With  regard  to  the  diseased  specimens  of  rainbow  trout  which  I  brought  to  you  recently,  I  visited 
the  Masterton  hatchery  on  June  16,  when  the  manager  was  engaged  in  shifting  his  3-year-old  rainbow 
trout  from  their  summer  ponds  into  the  spawning  races,  where  they  were  sorted  out,  i.  e.,  the  male  fish 
were  separated  from  the  females  and  the  ripe  female  fish  from  the  unripe;  the  ripe  fish  being  stripped, 
and  the  unripe  females  and  male  fish  being  put  into  separate  races.  I  assisted  with  the  separating  and 
stripping  that  day,  when  1,200  fish  were  handled.  From  this  number  29  fish  affected  with  this  gill 
tumor  were  taken  out;  these  (with  the  exception  of  the  specimens  taken  to  your  laboratory)  were 
knocked  on  the  head  and  buried. 

At  the  Otago  Acclimatization  Society's  Opoho  and  Clinton  trout  hatcheries  the  American  brook 
trout  are,  I  believe,  the  only  fish  affected  with  this  disease,  but  at  Christchurch  hatchery  I  understand 
that  it  is  common  among  both  the  American  brook  and  rainbow  trout.  If  it  is  of  any  interest  to  you  I 
will  get  particulars  from  the  Otago  and  Canterbury  Acclimatization  Societies  with  regard  to  this  matter, 
and  will  also  inquire  whether  this  disease  has  made  its  appearance  at  the  Aukland  Society's  hatchery 
at  Okoroire ,  where  only  rainbow  trout  are  kept. 

Gilruth  quotes  Ayson  further  as  the  authority  for  the  statement  that  at  Masterton 
he  was  present  at  the  handling  of  3,000  or  4,000  pond-spawning  fish  (1902)  and  that,  from 
these,  loo  fish  affected  similarly  to  those  described  were  taken  out  and  killed;  also  that 
the  manager  of  the  Aukland  Society's  rainbow  trout  hatchery  stated  that  7  per  cent  of 
the  mature  pond  fish  at  that  hatchery  were  affected. 

Marsh  in  1903  first  reported  the  disease  in  the  United  States  as  an  occasional 
occurrence  known  to  fish  culturists,  affecting  yearling  as  well  as  older  trout,  and  noted 
the  occurrence  of  marked  anemia  in  affected  fish. 

In  the  Third  Annual  Report  of  the  Imperial  Cancer  Research  Fund  (English),  1908, 
in  an  article  on  the  zoological  distribution  of  cancer  in  fishes,  occurs  the  following: 

Since  the  first  authentic  case  of  carcinoma  in  a  fish,  viz. ,  of  the  thyroid  gland  in  a  trout,  was  submitted 
to  us  in  February,  1903,  by  Mr.  Gilruth,  over  2,000  additional  cases  have  been  reported  to  us  from  the 
same  and  other  hatcheries.  *  *  *  We  have  been  unable  to  approach  this  extremely  interesting  and 
important  subject  from  the  fact  that  up  to  the  present  we  have  been  unable  to  find  any  evidence  of  its 
occurrence  in  the  hatcheries  in  this  country  at  the  present  time,  the  last  epidemic  of  the  disease  appear- 
ing in  1888  in  Scotland. 

At  a  meeting  of  the  Lyon  Medicale  in  1908  Jaboulay  reported  having  had  in  his 
laboratory  for  study  six  trout  affected  with  malignant  tumors  of  the  thyroid  gland. 
These  were  sent  to  him  in  November  by  M.  Crettiez,  inspector  of  waters  and  forests  of 
Thonon.  The  disease  had  existed  at  the  establishment  at  Thonon  for  three  years  and 
had  been  first  noticed  by  M.  Crettiez  in  salmon  hatched  from  eggs  received  from  Germany. 
He  had  recently  observed  the  disease  in  sea  salmon,  ombres-chevaliers  (Sahelinus 
alpinus),  and  in  the  offspring  of  one  hybridization  formed  by  crossing  the  common 
female  trout  with  the  male  ombres-chevaliers,  to  which  he  had  given  the  name  Salmo 
thononensis.  To  Crettiez  the  disease  appeared  to  be  clearly  hereditary  and  at  the  same 
time  contagious  and  always  fatal,  although  any  elaboration  of  his  grounds  for  these 
conclusions  is  not  given  by  Jaboulay.  Jaboulay  considers  the  tumor  an  adeno-carcinoma 
of  the  thyroid,  which  he  says  invades  the  thyroid  region  and  the  neighboring  tissues  and 
in  its  last  stages  generalizes  in  the  various  organs. 


372  BULLETIN  OF  THE   BUREAU  OF  FISHERIES. 

In  the  United  States  the  disease  has  been  known  to  fish  culture  for  some  40  years, 
but  has  escaped  mention,  so  far  as  we  have  been  able  to  find,  in  the  several  treatises  on 
fish  culture  which  have  been  written  in  this  country,  and  has  not  until  recently  been  the 
subject  of  any  particular  study. 

From  time  to  time  during  the  progress  of  this  investigation  we  have  made  prelimi- 
nary statements  before  the  American  Association  for  Cancer  Research.  These  brief 
summaries  are  here  reprinted  in  order  to  show  the  development  of  the  investigation  along 
the  lines  originally  indicated. 

AN   EPIDEMIC   OF  CARCINOMA   OF   THE   THYROID  GLAND  AMONG  FISH.° 

Dr.  Harvey  R.  Gaylord,  Buffalo:  This  paper  is  a  continuation  of  a  preliminary  report  made  before 
the  society  a  year  ago.  It  gives  details  of  two  epidemics  in  different  parts  of  the  country,  and  refers  to 
two  others.  The  epidemic  referred  to  last  year,  which  resulted  in  the  loss  of  3,500  brook  trout,  had, 
during  the  summer  of  1909,  begun  to  involve  the  brown  trout  and  adult  rainbows,  so  that  heavy  losses 
continued  during  this  summer.  Among  the  fish  preserved  from  this  epidemic  was  one  with  a  tumor 
on  the  lower  jaw,  which  on  section  was  found  to  be  either  an  implantation  of  the  thyroid  tumor  or  a 
metastasis,  as  the  fish  so  affected  had  a  primary  tumor  of  the  thyroid.  From  this  observation  it  is  plain 
that  this  tumor  may,  under  given  conditions,  metastasize,  or  that  it  is  implantable.  In  an  epidemic 
in  a  second  hatchery,  an  analysis  of  the  course  of  the  disease  again  showed  that  where  fish  occupied 
ponds  which  received  water  from  ponds  containing  infected  fish,  these  fish  may  become  infected; 
and,  furthermore,  the  rate  at  which  the  fish  become  involved  increases  progressively  as  the  contents 
of  ponds  containing  infected  fish  are  added  to  the  water  which  supply  the  fish.  Another  observation 
of  importance  is  the  discovery  that  lots  of  fish  are  immune.  This  is  particularly  shown  in  hybrid  fish, 
in  which  one  lot  of  hybrid  salmon  i  year  old  were  reduced  from  1,043  m  April  to  44  sound  fish  remain- 
ing in  August,  whereas  another  lot  of  yearling  hybrid  salmon,  although  badly  exposed  by  being  placed 
in  ponds  into  which  the  water  from  infected  ponds  ran,  remained  free  from  the  disease  throughout. 
Three  lots  of  Scotch  sea  trout  remained  immune,  although  badly  exposed.  The  only  lot  of  brook  trout 
2  years  old  which  were  free  from  the  disease  was  found  on  a  careful  analysis  of  their  position  throughout 
their  entire  life  history  in  this  hatchery,  never  to  have  been  placed  where  the  water  from  infected  troughs 
or  ponds  flowed  to  them.  They  were  placed  in  the  uppermost  pond  and  remained  free  from  the  disease 
throughout  the  epidemic.  These  observations  on  immunity  in  hybrid  fish,  in  the  light  of  those  made  by 
Tyzzer  in  inoculation  of  Japanese  waltzing-mouse  tumor,  in  hybrids  from  immune  and  nonimmune 
parents,  serve  to  accentuate  the  similarity  of  this  disease  in  fish  to  cancer  in  warm-blooded  animals. 

The  disease  is  found  to  affect  very  small  fish.  A  brook  trout  of  the  hatch  of  1909,  3  inches  in  length, 
was  shown  with  a  tumor  of  considerable  size  from  which  it  had  died.  This  was  the  first  affected  fish 
from  the  hatch  of  1909,  and  it  had  occupied  from  May  until  September  one  of  five  troughs  which  had 
the  previous  summer  contained  infected  fish.  From  this  it  would  appear  that  the  contagion  can  be 
localized,  even  to  given,  small  wooden  troughs,  and  that  these  troughs  can  retain  their  infectivity  from 
year  to  year.  In  all  the  epidemics  thus  far  described,  occasionally  large  fish,  when  exposed,  acquire 
the  disease.  A  landlocked  salmon  8  years  old,  measuring  24  inches  in  length,  developed  large  tumors, 
and  in  two  other  hatcheries  during  the  past  year  epidemics  have  broken  out  involving  considerable 
numbers  of  adult  rainbow  trout  and  large  adult  brook  trout.  Among  the  large  fish  epithelioma  of  the  tongue 
or  the  region  of  the  mouth  is  not  uncommon.  Carcinoma  of  the  thyroid  produces  the  most  rapid  destruc- 
tion among  young  fish,  frequently  diffusely  infiltrating  the  gills  and  also  growing  to  great  relative  size 
in  the  small  fish.  The  tumor  erodes  bone,  destroys  cartilage,  and  infiltrates  the  muscular  structure. 
The  tumor  presents  varying  characteristics,  frequently  retaining  the  alveolar  type  with  colloid,  again 
of  a  strictly  adenomatous  type,  but  in  all  cases  with  areas  of  complete  malignant  degeneration  and 
assuming  the  characteristics  of  solid  soft  carcinoma. 

o  American  Association  for  Cancer  Research,  meeting  of  Nov.  27, 1909,  Journal  American  Medical  Association,  Jan.  15,  1910. 


CARCINOMA  OF  THE  THYROID  IN  SAUVTONOID  FISHES.  373 

In  the  study  of  this  interesting  form  of  cancer,  the  discovery  of  metastasis  formation,  the  evidences 
of  immunity,  and  the  influence  of  blood  relationship  to  susceptibility  show  the  practical  identity  of 
this  affection  to  cancer  in  warm-blooded  animals.  The  apparent  absence  of  metastasis  formation  as  a 
criticism  was  long  since  applied  to  mouse  cancers  and  to-day  falls  to  the  ground  in  this  affection.  The 
evidence  of  infectivity  and  contagion  appear  to  the  observer  to  be  conclusive,  and  when  correlated  in 
the  evidence  of  infectivity  in  cancer  in  warm-blooded  animals  should  prove  the  greatest  support  to  the 
parasitic  theory  we  have  yet  encountered.  The  marked  evidence  of  infectivity  and  contagion  found 
in  carcinoma  of  the  thyroid  in  fish  appears  to  be  an  accentuation  of  similar  evidence  of  a  less  convincing 
character  found  in  other  species.  Its  accentuation  in  this  disease  can  be  largely  explained  by  the  envi- 
ronment and  the  conditions  under  which  fish  are  artificially  propagated. 

AN   EPIDEMIC  OF  CANCER  OF  THE   THYROID  IN   BROOK   TROUT  IN    A  FISH   HATCHERY.0 

Dr.  H.  R.  Gaylord,  Buffalo:  This  is  a  preliminary  report  on  the  investigation  of  a  fish  hatchery  in 
which  an  epidemic  of  carcinoma  of  the  thyroid  in  a-year-old  brook  and  brown  trout  exists  at  the 
present  time.  In  this  hatchery  the  water  supply  is  from  a  spring  coming  out  of  a  hillside,  which  runs 
into  a  basin  or  pond,  from  which  it  is  piped  to  a  small  reservoir  and  then  through  a  series  of  tanks  which 
draw  their  supply  directly  from  the  reservoir.  Carcinoma  of  the  thyroid  was  discovered  in  a  fish  in  the 
basin  on  the  hillside  two  years  ago.  One  year  ago  this  basin  was  emptied  and  restocked  with  young 
fish  and  feeding  was  practiced  for  the  first  time  in  this  upper  pond.  Of  the  tanks  fed  from  the  water 
passing  through  this  pond,  one  tank  containing  3,700  brook  trout  2  years  old,  hatched  from  eggs  brought 
from  a  hatchery  in  an  adjoining  State  where  the  disease  is  not  known  to  exist,  showed  700  fish  in  various 
stages  of  the  disease.  The  outbreak  occurred  in  the  early  autumn  and  fresh  cases  are  continually  devel- 
oping. In  an  adjoining  tank,  which  has  no  connection  whatsoever  with  the  tank  in  question,  are  200 
brown  trout  reared  from  eggs  hatched  on  the  premises.  Between  3  and  4  per  cent  of  these  fish  show 
disease.  The  infected  fish  at  no  time  have  come  in  direct  contact  with  the  fish  in  the  upper  pond 
where  the  disease  is  known  to  have  existed ;  neither  at  any  time  have  the  brook  trout  and  the  brown  trout 
been  in  contact  with  each  other.  I  believe  that  the  state  of  affairs  found  in  this  fish  hatchery  points 
very  strongly  to  the  infectious  nature  of  this  form  of  cancer  and  that  the  contagion  is  water-borne.  It 
is  possible  that  feeding  liver  into  the  waters  of  the  fish  hatchery  has  some  relation  to  the  outbreak  in  this 
case.  I  know  of  a  second  fish  hatchery  where  the  disease  was  endemic  for  a  number  of  years  and  where 
the  feeding  of  liver  has  been  changed  to  the  feeding  of  chopped  sea  fish  and  in  the  last  three  years  the 
disease  has  disappeared.  I  also  know  of  two  other  fish  hatcheries  in  which  the  disease  is  endemic,  and 
I  am  undertaking  a  systematic  and  careful  study  of  a  number  of  fish  hatcheries  for  the  purpose  of  further 
determining  the  conditions  under  which  the  disease  occurs. 

NORMAL  THYROID  IN  SALMONOIDS. 

The  thyroid  in  fishes  has  given  rise  to  a  not  inconsiderable  literature,  beginning  with 
Simon's  paper  (1844)  on  the  comparative  anatomy  of  the  gland,  in  which  he  first  identified 
the  thyroid  in  fishes.  The  detailed  studies  of  its  histology  belong  to  a  much  later  period. 
Most  of  the  work  has  been  upon  genera  outside  the  Salmonidae,  and  especially  upon  the 
lower  forms  of  fishes.  Maurer  (1886)  described  and  illustrated  the  development  of  the 
thyroid  in  a  trout,  and  the  location  of  the  thyroid  follicles  in  the  adult,  with  a  semi- 
diagrammatic  drawing  of  the  histology  of  the  adult  follicles.  In  1910  and  1911  Marine 
and  Lenhart  published  photomicrographs  of  normal  thyroid  in  the  brook  trout  in 
illustration  of  studies  of  enlargement  of  the  gland.  Thompson  in  1911  published  a 
paper  on  the  thyroid  and  parathyroid  of  vertebrates,  with  Amiurus  as  the  only  teleost 

»  American  Association  for  Cancer  Research,  meeting  of  Nov.  37, 1908,  Journal  of  American  Medical  Association,  Jan.  jo.  1909. 


374  BULLETIN   OF  THE  BUREAU   OF  FISHERIES. 

representative.  In  1911  Gudernatsch,  in  the  most  extended  study  of  the  fish  thyroid 
that  has  yet  appeared,  diagramed  the  distribution  of  the  follicles  in  22  genera  of  teleosts 
including  4  genera  and  5  species  of  salmonoids,  and  showed  the  minute  structure  in 
several  genera  including  2  species  of  salmonoids,  viz. ,  a  Pacific  salmon  and  the  American 
brook  trout  (Salvelinus  fonfanalis}.  He  was  the  first  to  emphasize,  in  a  preliminary 
statement  before  the  American  Society  for  Cancer  Research  (Nov.  27,  1909),  the  lack  of 
a  capsule  in  the  thyroid  of  teleosts. 

It  is  thus  seen  that  a  number  of  studies  having  to  do  with  normal  fish  thyroid  have 
been  made,  and  are  widely  scattered  among  the  many  and  diverse  genera  of  this  great 
class.  Not  until  recently  has  any  particular  attention  been  focused  upon  the  Salmonidse. 
The  amount,  distribution,  and  structure  of  the  gland  may  be  said  to  have  been  shown  for 
individuals  whose  source  and  history  and  the  conditions  under  which  they  had  been 
living  are  not  well  known  or  are  not  stated,  but  which  are  presumptively  normal  and 
show  no  obvious  pathologic  changes.  If,  however,  one  limits  the  normal  to  the  minimum 
of  the  thyroid  exhibited  by  adults  from  streams  far  from  and  unaffected  by  civilization, 
where  the  fish  are  obviously  living  strictly  in  a  state  of  nature,  there  is  yet  but  a  meager 
exposition  of  the  normal  thyroid  in  the  salmonoids.  We  believe  that  the  final  comparison 
is  to  be  against  a  norm  set  up  by  such  individuals,  and  that  most  trout  from  aquariums, 
markets,  fish-cultural  establishments,  and  from  artificially  stocked  streams  and  lakes  or 
unstocked  streams  or  lakes  close  to  civilization  or  much  frequented  by  people,  have 
either  abnormal  thyroids  or  are  not  to  be  judged  by  criteria  obtained  from  strictly 
wild  trout. 

In  our  specimens  of  wild  brook  trout  we  are  unable  to  find  the  thyroid  distributed 
as  widely  and  in  such  quantity  as  shown  by  Gudernatsch  (1911,  a,  p.  753  and  pi.  n)  for 
this  species.  He  finds  it  extending  into  the  gill  arches,  infiltrating  muscle  bundles  and 
in  places  completely  filling  the  available  thyroid  spaces.  We  find  these  conditions  in 
domesticated  fish,  but  not  in  our  wild  specimens.  His  material  was  in  part  obtained  from 
aquarium  fish,  and  in  such  we  would  expect  such  a  distribution.  It  may  even  occur 
in  specimens  from  some  streams  or  lakes.  We  would  infer  that  all  fish  exhibiting  it 
may  be  presumed  to  have  been  under  influences  foreign  to  those  usually  obtaining  in 
strictly  wild  natural  conditions,  but  they  may  perhaps  be  considered  to  represent  a 
normal  for  trout  under  a  modified  regime  without  presumption  of  any  definite  pathologic 
change.  The  minimum  quantity  of  thyroid  and  its  more  restricted  distribution  appear 
to  us  as  affording  a  more  representative  picture  of  the  ultimate  normal.  Maurer,  while 
not  mapping  in  detail  the  distribution  in  the  adult,  describes  a  condition  which  speaks 
for  the  more  confined  arrangement  of  thyroid  tissue  (fig.  5  and  6). 

EMBRYOLOGY. 

Maurer  (1886)  has  described  the  development  of  the  thyroid  in  trout.  According 
to  his  observations,  about  the  twenty-seventh  day  after  fertilization,  the  embryo  being 
6  millimeters  long,  an  unpaired  median  evagination  arises  from  the  ventral  epithelium 
of  the  pharynx  (fig.  7).  This  is  the  earliest  differentiation  of  thyroid.  It  lies  in  front 
of  the  heart  in  the  bifurcation  of  the  heart  tube  into  the  hvoid  arteries,  and  consists 


CARCINOMA   OP  THE   THYROID   IN    SALMONOID   FISHES.  375 

of  several  layers  of  cubical  cells.  At  this  time  no  cartilage  is  differentiated,  but  the 
hyoid  arch  is  well  developed  and  the  true  gill  arches  are  indicated,  the  brain  vesicles 
and  mouth  opening  are  present,  while  the  only  macroscopic  vessels  of  the  region  are 
the  S-shaped  heart  tube  and  the  two  hyoid  arteries. 

The  primary  evagination  lies  close  but  not  attached  to  the  arterial  wall,  from  which 
it  is  separated  by  connective  tissue.  At  32  days  it  has  become  spherical,  has  a  lumen 
of  its  own,  its  epithelium  is  single  layered  and  is  connected  with  the  mother  cells  only 
by  a  slender  pedicle.  (Fig.  8.)  At  35  days  it  has  completely  separated  (fig.  9),  is 
about  0.04  millimeter  in  diameter,  and  lies  exactly  in  the  fork  of  the  heart  tube,  which 
is  o.i  millimeter  in  diameter  before  the  bifurcation.  The  four  pairs  of  true  gill  arteries 
are  now  visible. 

During  the  next  six  days  the  vesicle  becomes  somewhat  elongated  and  changes  its 
position.  It  now  measures  about  0.03  by  0.06  millimeter  and  has  been  pressed  back 
of  the  bifurcation  and  lies  ventral  to  the  gill  artery  trunk,  or  ventral  aorta  (fig.  10). 
Colloid  is  now  present  and  the  vesicle  begins  to  put  out  buds  which  rapidly  develop  a 
lumen  filled  with  colloid  and  quickly  separate.  These  multiplying  buds  grow  around 
the  aorta  to  the  dorsal  side  and  keep  pace  with  its  increase  in  length  until,  at  77  days 
or  3  weeks  after  hatching,  that  portion  of  the  aortic  trunk  from  the  last  branchial 
arteries  forward  to  the  bifurcation  is  surrounded  by  thyroid  follicles.  Finally,  thyroid 
growth  failing  to  keep  pace  with  the  lengthening  of  the  ventral  aorta,  the  adult  con- 
dition is  approached  when  the  thyroid  mass  breaks  up  into  irregular  deposits  or  clusters 
of  follicles  which  remain  in  the  vicinity  of  the  ventral  aorta. 

In  the  adult  trout  the  greater  portion  of  the  thyroid  is  dorsal  to  the  aorta.  Maurer's 
description  therefore  requires  that  it  migrate,  from  its  origin  dorsal  to  the  heart  tube, 
to  the  ventral  side  of  the  aorta  and  then  back  again  to  the  dorsal  side,  and  this  view  is 
confirmed  by  our  specimens. 

While  colloid  no  doubt  appears  very  early  in  the  embryo  and  before  the  latter 
leaves  the  eggshell,  Maurer's  statement  that  it  appears  about  the  forty-first  day  of 
incubation  is  indefinite,  since  incubation  proceeds  over  a  considerable  range  of  tem- 
perature and  is  much  more  rapid  in  the  warmer  water.  The  stage  of  incubation  may 
be  accurately  stated  in  temperature  units  when  both  time  and  temperature  are  known. 
From  the  facts  at  hand,  however,  it  may  be  expected  that  all  normal  trout  embryos 
have  developed  colloid  as  soon  as  the  hatching  stage  is  reached. 

In  our  specimens  of  hatchery  brook  trout  still  in  the  sac  stage,  but  some  days 
hatched,  colloid  is  plainly  visible  (fig.  13)  in  many  follicles.  The  amount  and  location 
of  thyroid  tissue  is  even  at  this  early  stage  subject  to  considerable  variation.  The 
follicles  are,  however,  always  relatively  few.  In  three  examples  the  total  number  of 
distinct  follicles  recognizable  by  serial  sections  throughout  the  floor  of  the  mouth  was 
24,  27,  and  33,  respectively.  In  other  cases  there  appears  to  be  a  smaller  number.  In 
distribution  two  more  or  less  distinct  deposits  are  recognizable,  besides  scattered  folli- 
cles. One  of  these  is  at  or  in  front  of  the  level  of  the  epithelial  invagination  which  is 
to  become  the  jugular  pit,  a  region  which  will  be  shown  later  to  be  the  seat  of  thyroid 
deposits  in  the  adult.  At  this  stage  it  is  already  a  very  definite  infolding.  The  follicles 


376  BULLETIN  OF  THE  BUREAU  OF  FISHERIES. 

are  here  in  close  relation  to  and  not  infrequently  lie  in  actual  contact  with  (fig.  10)  the 
cells  of  this  imagination,  and  thus  illustrate  the  probable  origin  of  pit  tumors.  One 
or  more  of  the  thyroid  follicles  can  be  easily  dragged  away  from  their  neighbors  with 
the  growth  of  the  pit  region  and  come  to  lie  immediately  beneath  the  pit  epithelium, 
as  has  been  remarked  in  the  discussion  of  distribution  (fig.  14).  When  the  thyroid 
later  proliferates  abnormally,  an  independent  tumor  begins  to  occupy  the  jugular  pit. 

In  the  adult  scarcely  any  thyroid  is  located  so  far  forward  as  in  these  recently 
hatched  fry,  where  in  the  neighborhood  of  the  pit  it  is  to  be  found  cephalad  of  the  first 
arch  and  of  the  bifurcation  of  the  aorta.  The  other  deposit  or  aggregation  of  follicles 
centers  in  the  region  occupied  by  the  adult  thyroid,  or  in  the  vicinity  of  the  second  arch. 
They  are  not  arranged  with  any  regularity,  were  not  observed  in  any  case  to  extend 
laterally  upon  the  gill  arches  but  scatter  along  directly  beneath  the  mesal  bridge,  and 
reach  in  a  few  cases  as  far  back  as  the  beginning  of  the  fourth  arch.  Between  the 
follicles  about  the  jugular  pit  and  those  in  the  vicinity  of  the  second  arch,  a  gap  usually 
intervenes  in  which  no  thyroid  occurs.  The  limits  of  variation  in  amount  and  position 
of  thyroid  tissue  can  not  be  defined  here,  but  from  the  material  examined  it  appears 
that  either  of  the  chief  groups  of  follicles  as  just  described  may  in  some  specimens  be 
entirely  wanting,  and  that  the  adult  gland  may  develop  from  one  of  these  groups  alone. 

GROSS  ANATOMY  AND  DISTRIBUTION  IN  THE  ADULT  BROOK  TROUT. 

While  the  thyroid  is  not  a  definite  gland  unit  and  on  account  of  its  small  size,  sepa- 
ration into  discrete  aggregates,  and  lack  of  encapsulation  can  not  be  extirpated,  or 
dissected  free  in  its  entirety,  it  is  nevertheless  macroscopic  in  adult  trout.  On  medi- 
section  of  the  floor  of  the  mouth,  delicate  small  masses  of  tissue  may  be  seen  about  the 
ventral  aorta  near  the  first  and  second  arches  between  the  vessel  and  the  cartilages 
and  bone  of  the  mesal  bridge  into  which  the  gill  arches  unite.  These  masses  contain 
the  chief  aggregates  of  thyroid  follicles,  and  consist  in  large  part  of  connective  tissue. 
They  are  likely  to  be  found  close  to  the  second  gill  arch,  and  more  likely  to  lie  opposite 
the  interspaces  between  the  arches  than  opposite  the  arch  itself.  Under  a  hand  or 
dissecting  lens  the  individual  follicles  may  be  recognized  embedded  in  the  mass.  Only 
the  massed  follicles  are  to  be  seen  with  the  naked  eye  and  therefore  the  outlying  small 
deposits  are  not  demonstrable  save  on  microscopic  section.  The  macroscopic  thyroid 
masses  in  wild  fish  will  only  be  found  close  to  the  middle  line  and  at  or  just  in  front 
of  or  behind  the  second  arch.  Such  masses  closely  resemble  in  appearance  the  fatty 
and  areolar  tissues  which  contain  no  thyroid,  and  can  not  be  recognized  with  certainty 
as  thyroid  without  a  lens. 

The  exact  location  of  thyroid  follicles  in  the  adult  is  variable.  Perhaps  every  fish 
gives  a  recognizably  distinct  distribution  pattern.  To  understand  the  location  of  the 
thyroid  some  consideration  of  the  anatomy  of  the  skeletal  and  other  parts  of  the  floor 
of  the  mouth  is  necessary.  There  are  five  pairs  of  branchial  arches,  of  which  only  the 
cephalic  four  bear  gills.  Each  arch  save  the  fifth  is  composed  of  several  bones,  of 
which  the  ventral,  or  hypobranchial,  is  united  with  its  fellow  of  the  opposite  side  by  the 
mesal  unpaired  basibranchial,  and  by  cartilaginous  copulae  which  thus  form  the  links 


CARCINOMA   OP  THE  THYROID  IN  SALMONOID  FISHES.  377 

between  the  right  and  left  halves  of  each  pair  of  arches.  The  basibranchials  are  con- 
nected with  each  other  by  these  same  cartilaginous  copulae,  so  that  a  solid  mesal  bridge 
is  formed  on  the  floor  of  the  mouth,  continuous  with  the  tongue  and  reaching  back  to 
the  fourth  arch.  The  basibranchials  lie  opposite  the  interspaces  between  the  arches, 
while  the  copulae  lie  opposite  the  arches  themselves.  The  first  and  second  basibranchials 
are  well  ossified,  the  third  less  so,  and  the  fourth  is  mostly  cartilage. 

Immediately  beneath  this  bridge  runs  the  ventral  aorta.  The  bulbous  aorta  is 
located  deeper,  well  beneath  the  floor  of  the  mouth  and  somewhat  back  of  the  fourth 
arch.  From  it  the  ventral  aorta  runs  dorsocephalad  to  a  point  just  under  the  third 
arch.  Here  are  given  off  the  two  trunks  which  soon  bifurcate  into  the  third  and  fourth 
branchial  arteries  supplying  the  corresponding  gills.  Thence  the  ventral  aorta  runs 
cephalad  and  slightly  ventrad.  Near  the  caudal  margin  of  the  second  arch  the  second 
pair  of  branchial  arteries  is  given  off,  supplying  the  second  pair  of  gill  arches.  Finally 
the  ventral  aorta,  just  as  it  reaches  the  first  arch,  bifurcates  into  the  first  pair  of  branchial 
arches.  A  certain  amount  of  space  is  left  about  the  ventral  aorta  between  it  and  the 
parts  which  inclose  it.  This  space  is  greater  dorsal  to  the  vessel,  and  especially  at  the 
origins  of  the  first  and  second  pairs  of  branchial  arteries.  It  contains  the  normal  thyroid 
and  its  supporting  tissues. 

Figures  15  and  16  illustrate  the  lateral,  longitudinal,  and  dorsoventral  distribution 
of  normal  thyroid.  They  represent  the  condition  in  no  single  fish,  but  show  compositely 
a  probable  average  from  a  number  of  individuals.  Two  chief  masses  of  thyroid  may 
usually  be  recognized,  the  follicles  clustering  at  and  back  of  the  first  and  second  pair  of 
branchial  arteries,  with  usually  a  definite  space  between  them  in  which  but  few  and 
scattered  follicles  occur.  Occasionally  three  masses  or  groups  are  recognizable,  and  the 
masses  themselves  present  irregularities  in  the  arrangement  and  number  of  follicles. 
Exact  medisections  show  less  thyroid  than  those  slightly  sagittal  on  account  of  the 
extension  of  the  copulas  and  basibranchials  to  the  aorta  at  the  second  and  third  arches 
on  the  mesal  line. 

We  have  not  found  in  the  normal  wild  fish  studied  by  us  any  lateral  extension  of  thy- 
roid structure  along  the  branchial  arches.  Most  of  it,  in  fact,  hardly  reaches  the  lateral 
margins  of  the  mesal  bridge.  The  most  cephalic  extensions  rarely  reach  the  first  basi- 
branchial,  and  on  the  mesal  line  scarcely  to  the  first  copula.  The  extreme  caudal  exten- 
sion is  to  the  fourth  arch,  but  usually  there  are  but  few  follicles  either  at  or  behind  the 
third  pair  of  branchial  arteries.  Follicles  are  present  in  bone  spaces,  but  in  normal  wild 
trout  we  have  never  found  them  among  the  muscle  bundles.  They  are  frequently  em- 
bedded in  the  fatty  tissue  network  or  lie  loosely  attached  to  the  vessels  or  other  tissues, 
but  never  show  any  invasive  tendency,  nor  do  the  follicles  occupy  more  than  a  part  of 
the  apparently  available  space  of  the  thyroid  region. 

ANOMALOUS  DEPOSITS  OF  THYROID. 

In  a  quantitative  sense  all  the  thyroid  of  importance  is  confined  to  the  immediate 
vicinity  of  a  portion  of  the  ventral  aorta.  As  the  thyroid  is  a  somewhat  diffuse  organ 

8207° 14 2 


378  BULLETIN   OF  THE  BUREAU   OF  FISHERIES. 

one  might  expect  to  find  instances  of  remotely  placed  deposits.  We  are  therefore 
surprised  to  find  the  sharp  delimitation  to  the  region  already  described  which  appears  to 
exist  in  our  wild  specimens,  with  one  marked  exception,  i.  e.,  the  jugular  pit  to  which 
reference  has  already  been  made.  It  has  been  assumed  by  some  writers  that  aberrant 
thyroid  deposits  in  some  regions  might  be  frequently  expected.  This  has  been  due  to 
the  development  of  tumor  nodules  in  regions  beyond  the  normal  and  usual  seat  of 
distribution,  such  as  the  lower  mouth  parts  and  gill  arch  region.  The  only  outlying 
tumors  of  this  sort  which  may  be  inferred  with  certainty  to  arise  from  original  deposits 
of  thyroid  are  the  so-called  pit  tumors. 

In  the  adult  trout  there  occurs  on  the  ventral  side  of  the  head  between  the  dentary 
bones  a  median  irregular  depression  or  blind  pit  open  to  the  exterior.  It  is  the  region 
where  the  muscles  between  the  dentaries  and  those  of  the  branchiostegals  become 
common.  The  skin  dips  into  its  ramifications  with  many  plications  and  infoldings. 
It  is  an  entirely  superficial  and  exterior  landmark,  and  though  independent  of  and  well 
removed  from  the  thyroid  region  in  the  adult,  is  of  some  importance  in  thyroid  pathology, 
since  at  an  early  stage  it  is  in  closely  apposed  relation  to  the  thyroid  region,  and  is  the 
occasional  seat  of  detached  thyroid  follicles  and  of  independent  thyroid  tumors.  This 
much  branched  and  partitioned  cavity  may  be  designated  as  the  jugular  pit  (fig.  n). 
It  may  be  recognized  at  or  soon  after  the  hatching  of  the  embryo.  Normal  thyroid 
has  been  several  times  observed  immediately  beneath  the  pit  epithelium  in  wild  brook 
trout  (fig.  14),  where  its  presence  may  be  readily  explained  by  the  mechanics  of  devel- 
opment of  the  parts  (fig.  12).  Since  of  91  trout  with  tumors,  25  showed  pit  tumors,  one 
may  conclude  that  more  than  one-quarter  of  all  brook  trout  have  normally  some  thyroid 
follicles  in  the  region  of  the  pit. 

Occasionally  detached  tumors  develop  in  the  gill  arches.  We  have  never  actually 
seen  thyroid  follicles  on  the  free  portions  of  the  gill  arches,  and  there  is  little  embryo- 
logical  presumption  in  favor  of  such  deposits,  notwithstanding  the  relation  of  the  gill 
arches  with  the  thyroid  region.  The  tip  of  the  lower  jaw  has  even  much  less  anatomical 
relation  to  the  thyroid  region,  rendering  it  an  unlikely  place  for  stray  follicles.  The 
examination  by  serial  sections  of  the  tips  of  the  lower  jaws  of  about  25  trout  failed  to 
show  any  thyroid  here.  The  region  is  called  into  question  as  a  seat  of  normal  thyroid 
deposit  on  account  of  the  rare  cases  of  a  thyroid  tumor  occupying  this  site.  The 
actually  observed  occurrence  of  normal  thyroid  in  the  pit  and  the  incidence  of  tumors 
here  make  it  extremely  probable  that  no  other  extralimital  deposits  occur  with  any 
frequency,  else  such  would  declare  themselves  in  tumor  formation. 

HISTOLOGY. 

A  closed  alveolus  is  the  unit  of  the  thyroid  gland.  These  alveoli  are  apparently 
independent  of  each  other  save  as  they  are  more  or  less  bound  together  by  the  vascular 
framework  and  connective  tissue  stroma.  Their  lumina  have  no  connections  with 
each  other  and  each  alveolus  independently  discharges  its  secretion  into  the  circulation. 
Many  alveoli  are  quite  isolated  from  their  kind  and  lie.  loosely  in  the  tissue,  whether 
connective,  muscle,  bone,  cartilage,  or  fat.  In  the  simplest  adult  condition  (fig.  14-21) 


CARCINOMA   OF   THE   THYROID   IN   SAUMONOID   FISHES.  379 

they  are  typically  spherical,  subspherical,  or  slightly  elongated,  and  consist  of  a  single 
layer  of  flattened  epithelium,  with  a  large  lumen  completely  filled  with  homogeneous 
colloid  readily  stainable  by  cytoplasmic  stains.  The  cells  of  this  epithelium  are  poly- 
hedral, very  flat,  with  very  deeply  staining  slightly  vesicular  nuclei,  lying  parallel  with 
the  longer  dimensions  of  the  cell.  The  nucleus  is  longer  than  wide,  about  as  thick  as  the 
short  diameter  of  the  cell,  but  its  other  dimensions  are  shorter  than  those  of  the  cell. 
In  size,  alveoli  show  wide  variation,  the  smallest  measuring  as  little  as  0.02  millimeter,  or 
even  less,  in  diameter.  From  these  all  sizes  are  to  be  found  up  to  plainly  macroscopic 
follicles  at  least  0.75  millimeter  across.  Perhaps  even  larger  ones  occur.  Most  of  the 
alveoli  of  course  fall  well  within  these  extremes.  Only  the  largest  are  visible  to  the  naked 
eye. 

There  is  thus  a  promptly  recognizable  similarity  between  the  structure  and  appearance 
of  the  thyroid  unit  in  the  trout  and  that  of  man  and  other  mammals.  The  entire  gland 
in  these  groups  is  similarly  comparable  in  location,  function,  and  perhaps  in  size,  though 
it  is  impossible  to  weigh  the  trout  thyroid  and  difficult  to  estimate  its  weight  or  bulk. 
The  chief  difference  between  the  gland  in  fish  and  mammals  lies  in  the  absence  from  the 
fish  thyroid  of  even  a  suggestion  of  a  capsule,  which  in  man  is  a  definite  and  important 
structure  which  completely  delimits  the  thyroid  from  the  neighboring  tissues  and 
confines  its  units  as  a  definite  gland  organ.  The  trout  thyroid  lies  in  the  various  tissues 
beneath  the  floor  of  the  mouth  without  any  very  definite  interstitial  tissue  of  its  own. 

For  the  normal  structure  of  the  thyroid  we  have  examined  trout  taken  from  natural 
waters  of  the  country,  such  as  streams  and  lakes  in  wild  and  unsettled  regions.  From 
these  it  is  apparent  that  there  is  no  inconsiderable  variation  in  the  thyroids  of  adult  fish 
in  their  natural  habitat.  This  variation  certainly  depends  largely  upon  age  and  season, 
is  no  doubt  in  part  individual,  and  is  in  our  opinion  also  a  function  of  other  causes  among 
which  is  the  nature  of  the  waters  inhabited,  whether  shallow,  rapidly  flowing  streams 
or  the  more  quiet  and  deeper  lakes.  These  natural  conditions  react  with  the  metabolism 
of  the  fish. 

The  simplest  condition  of  the  thyroid,  as  described  above,  was  seen  in  wild  brook 
trout  taken  in  January  from  the  Au  Sable  River  in  Michigan.  (Fig.  17.)  The  same 
species  taken  in  June  from  streams  in  Wisconsin  differ  in  showing  somewhat  higher 
epithelium,  which  may  be  regarded  as  cuboidal.  Our  specimens  from  these  two  sources 
show  the  simplest  or  lowest  epithelium,  in  most  cases  flattened  and  never  higher  than 
cuboidal.  Specimens  taken  in  May  from  a  lake  in  Algonquin  National  Park,  Ontario, 
Canada,  show  a  further  advance.  The  epithelium  is  distinctly  higher  and  the  general 
character  of  the  thyroid  picture  seems  to  us  to  separate  these  fish  from  the  other  groups 
of  wild  fish  discussed  above  and  to  justify  their  consideration  under  the  heading  of 
simple  hyperplasia. 

SIMPLE  HYPERPLASIA  AND  COLLOID  GOITER  IN  WILD  AND 
DOMESTICATED  FISH. 

The  picture  of  the  normal  thyroid  in  the  wild  Salmonidae  is  extremely  characteristic, 
and  although,  as  described,  considerable  variations  are  found  in  the  size  of  the  alveoli» 


380  BULLETIN   OP  THE   BUREAU   OF   FISHERIES. 

there  is  but  a  very  limited  range  of  change  in  the  epithelial  cells.  So  characteristic  is 
this  picture  that  it  is  possible  to  recognize  the  condition  of  simple  hyperplasia  of  the 
thyroid,  although  the  exact  relation  of  simple  hyperplasia  to  the  function  of  the  organ 
is  not  clear.  We  have  encountered  a  condition  of  the  thyroid  in  specimens  of  brook 
trout  taken  from  the  Algonquin  National  Park  in  Ontario,  Canada,  where  the  change 
is  sufficiently  marked  to  constitute,  in  our  opinion,  a  condition  of  simple  hyperplasia  in 
fish  living  under  wild  conditions.  (Fig.  18.)  The  specimens  were  taken  in  the  regular 
course  of  angling  on  several  days  in  Little  Island  Lake  in  the  park.  The  picture  pre- 
sented by  the  thyroid  of  these  fish  is  sufficiently  characteristic  to  permit  the  description 
of  the  thyroid  of  any  one  specimen  to  serve  for  the  rest.  As  compared  with  the  thyroid 
structure  of  Wisconsin  and  Michigan  wild  brook  trout,  the  alveoli  lie  more  closely  packed 
and  present  much  more  the  appearance  of  a  definite  organ  than  in  the  strictly  normal 
condition.  The  alveoli  are  of  much  more  irregular  shape,  presenting  irregular  forms 
and  protrusions,  smaller  pouch-like  additions  to  the  typical  spherical  or  oval  alveolar 
structure,  and  evidences  of  budding.  The  epithelium  is  high  cuboidal,  stains  more 
deeply,  and  the  long  axis  of  the  deeply  stained  nucleus  is  usually  perpendicular  to  the 
circumference  of  the  alveolus.  The  colloid  is  diminished  in  amount,  many  of  the 
smaller  alveoli  containing  little  or  none.  It  stains  less  deeply  than  in  the  normal  struc- 
ture. There  are  evidences  of  hyperaemia  in  the  stroma  and  the  stroma  is  much  richer 
in  small  cells  than  in  the  normal.  The  total  number  of  alveoli  seems  to  be  increased. 
We  have  not  seen  any  evidences  of  karyokinetic  figures  in  the  cells.  The  epithelium 
never  reaches  the  high  columnar  and  bizarre  shapes  found  in  the  early  stages  of  car- 
cinoma. The  entire  thyroid  structure  is  more  uniform  in  type. 

Simple  hyperplasia  of  the  thyroid  has  been  described  by  Marine  and  Lenhart  (1910) 
as  occurring  in  fish  obtained  from  Lake  Erie.  Pike  and  bass,  according  to  these  authors, 
are  commonly  affected;  sheepshead  and  herring  more  rarely.  They  also  report  an 
example  of  spontaneous  colloid  goiter  in  the  pike  which  they  consider  the  terminal  stage 
of  hyperplasia  that  has  undergone  resolution. 

A  simple  hyperplasia  of  this  type  undoubtedly  occurs  in  fish  under  domestication. 
It  is  impossible  to  distinguish  simple  hyperplasia  in  fish  hatcheries  from  the  first  stages 
of  carcinoma  of  the  thyroid,  a  difficulty  which  is  common  to  the  diagnosis  of  all  malignant 
tumors.  We  have  been  fortunate  in  having  for  study  at  Craig  Brook  a  variety  of  the 
Salmonidae  which  possesses  natural  immunity  to  carcinoma  of  the  thyroid.  These  fish 
are  the  Scotch  sea  trout  (Salmo  trutta  Linnaeus) .  The  original  stock  was  obtained  from 
abroad  as  eggs,  hatched  in  the  hatchery,  carried  through  its  various  troughs,  and  the 
adult  fish  ultimately  came  to  occupy  the  ponds  lying  in  a  position  where  they  received 
the  water  from  ponds  above,  in  which  carcinoma  of  the  thyroid  in  brook  trout  was 
extremely  prevalent.  The  facts  bearing  on  the  evidences  of  immunity  in  this  connection 
will  be  considered  later.  The  eggs  taken  from  these  domesticated  sea  trout  have  been 
again  hatched  in  the  hatchery,  maintained  in  the  outside  smaller  troughs,  and  we  have 
thus  had  an  opportunity  to  study  the  offspring  of  the  adult  fish  at  various  stages,  as 
well  as  the  condition  of  the  thyroid  in  the  larger  fish.  We  have  never  found  macroscopic 
evidence  of  even  the  earliest  stages  of  carcinoma  of  the  thyroid  in  the  younger  of  these 


CARCINOMA   OF  THE   THYROID   IN   SALMONOID   FISHES.  381 

fish.  The  examination  of  specimens  of  the  offspring  of  the  older  fish  at  the  fingerling 
stage  reveals  the  thyroid  of  occasional  specimens  in  a  state  of  simple  hyperplasia  (fig. 
20),  perhaps  slightly  more  marked  than  that  found  in  the  wild  fish  from  Algonquin 
Park.  (P.  75.) 

In  these  small  fish  the  thyroid  is  not  markedly  increased  in  amount  and  is  largely 
localized  about  the  great  vessels,  but  occasional  groups  of  alveoli  are  found  somewhat 
more  widely  removed  from  these  structures  than  normal,  and  occasional  small  groups  in 
the  infoldings  of  the  cartilage  or  bone  or  between  the  muscle  bundles.  The  alveoli  are 
not  unusually  large,  the  epithelium  is  high  cuboidal  and  low  columnar,  the  long  axes  of 
the  nuclei  perpendicular  to  the  circumference  of  the  alveoli.  Both  protoplasm  and 
nucleus  stain  more  deeply  than  normal.  The  colloid  is  diminished  in  amount  and  stains 
less  well  than  in  the  normal  specimens.  (See  fig.  20,  which  may  be  compared  with 
a  similar  photograph  at  the  same  magnification  of  a  Scotch  sea  trout  from  the  same  lot, 
2050  A,  fig.  19,  in  which  the  thyroid  structure  presents  a  characteristic  normal  appear- 
ance, and  both  may  be  compared  with  a  fish  of  similar  size  taken  in  the  wild  state  from 
the  Au  Sable  River,  Mich.,  fish  199  A,  fig.  19,  of  which  an  illustration  at  similar  magni- 
fication is  provided.)  The  thyroid  gland  of  the  adult  Scotch  sea  trout,  when  viewed  in 
the  light  of  the  conditions  found  in  the  smaller  fish,  in  which  occasional  examples  show 
simple  hyperplasia  and  the  larger  proportion  strictly  normal  thyroid  tissue,  reveals  a 
similar  division  in  character  of  the  thyroid  in  the  adults.  A  larger  proportion  of  the 
adult  Scotch  sea  trout  presents  strictly  normal  thyroid  tissue.  (Fig.  21.)  There  does 
not  appear  to  be  an  increased  amount  of  thyroid  for  the  size  and  age  of  these  fish.  The 
minority  of  the  fish,  however,  presents  microscopically  a  condition  of  the  thyroid  which 
may  be  spoken  of  as  colloid  goiter.  (Fig.  22.)  In  them  the  alveoli  are  greatly  increased 
in  size,  the  total  amount  of  thyroid  is  also  increased,  the  walls  of  the  alveoli  are  very 
thin,  the  epithelium  pressed  very  flat,  and  the  lumina  compactly  filled  out  with  large 
masses  of  colloid. 

From  a  careful  study  of  the  Scotch  sea  trout,  it  is  clear  that  although,  as  will  be 
shown  later,  they  are  almost  perfectly  immune  to  carcinoma  of  the  thyroid,  a  certain 
proportion  of  them  are  affected  by  a  process  of  simple  hyperplasia  which  terminates 
by  resolution  in  colloid  goiter.  It  will  be  shown  later  that  spontaneous  recovery  of 
carcinoma  of  the  thyroid  in  the  Salmonidae  produces  an  entirely  different  terminal 
picture  from  that  of  colloid  goiter.  In  the  instance  above  described  of  the  Scotch  sea 
trout,  the  transformation  of  hyperplasia  into  colloid  goiter  has  been  brought  about  by 
a  process  which  has  been  termed  resolution.  In  carcinoma  the  disappearance  of  the 
tumors  in  spontaneous  recovery  is  brought  about  by  a  process  of  regression,  a  part  of 
which  may  be  referred  to  as  resolution;  that  is,  the  epithelium  undergoes  changes  of 
type,  colloid  reappears,  but  the  bulk  of  the  tumor  literally  retrogrades.  Many  of  the 
alveoli  totally  disappear  and  large  areas  are  frequently  removed  so  rapidly  as  to  require 
extensive  repair  by  connective  tissue.  All  of  the  characteristic  appearances  found  in 
regression  of  malignant  mammalian  tumors,  such  as  the  frequency  of  large  areas  of  hem- 
orrhage followed  by  repair,  the  formation  of  pseudogiant  cells  by  coalescence  of  the 
epithelium,  great  increase  in  the  connective  tissue  stroma  especially  at  the  margins  of 


382  BULLETIN   OF  THE   BUREAU   OF  FISHERIES. 

the  tumor,  deposition  of  pigment  and  final  clearing  up  of  these  phenomena  with  total 
disappearance  of  the  tumor,  leaving  only  a  small  residue  of  approximately  normal 
functionating  thyroid  alveoli,  presents  a  picture  which  can  be  readily  distinguished  from 
the  characteristic  appearance  of  colloid  goiter,  as  found  in  the  Scotch  sea  trout.  From 
the  evidences  obtained  from  the  fish  from  the  Algonquin  National  Park,  we  are  of  the 
opinion  that  trout  in  the  wild  state  may  also  suffer  from  simple  hyperplasia  of  the  thyroid, 
which  also,  no  doubt,  would  terminate  by  resolution  in  colloid  goiter,  although  we  have 
not  been  fortunate  enough  to  secure  such  specimens  from  the  wild  state.  As  the  majority 
of  the  Scotch  sea  trout  under  the  conditions  we  have  studied  present  both  in  the  small 
fish  and  in  the  adults  a  preponderance  of  strictly  normal  thyroids,  it  is  obvious  that  this 
condition  is  not  the  direct  result  of  domestication,  the  existence  of  simple  hyperplasia 
in  wild  fish  making  this  deduction  obvious. 

Whether  simple  hyperplasia  leading  to  colloid  goiter  in  the  Scotch  sea  trout  is  a 
process  with  distinctive  etiology,  possibly  the  result  of  unusual  physiological  demand 
upon  the  organ,  or  a  greatly  modified  type  of  carcinoma  of  the  thyroid  occurring  in 
an  immune  species,  can  not  at  present  be  determined.  The  observation  in  one  or  two 
of  the  older  fish  of  red  floors,  and  one  or  two  reported  tumors  which  we  did  not  see, 
may  indicate  that  further  material  may  be  secured  which  will  throw  light  upon  this 
question.  For  the  present  we  would  recognize  a  simple  hyperplasia  not  associated  etio- 
logically  with  carcinoma  of  the  thyroid. 

PATHOLOGIC  ANATOMY. 

GROSS  ANATOMY. 
EARLIEST   MACROSCOPIC   EVIDENCE. 

The  first  evidence  of  thyroid  proliferation  visible  to  the  unaided  eye  is  the  so-called 
red  floor  (fig.  23  and  23a).  It  is  a  faint  reddening  or  flushing  of  the  median  area  of  the 
floor  of  the  mouth  usually  opposite  to  or  in  the  neighborhood  of  the  second  gill  arches. 
It  is  caused  by  the  increasing  blood  supply  of  the  main  thyroid  deposit  and  by  hyper- 
emia  of  adjacent  tissues,  which  show  through  the  epithelium.  Its  first  appearance  is 
sometimes  a  mere  streak,  more  often  a  circular  or  irregular  diffuse  reddening.  It  usually 
soon  spreads  more  widely,  reaching  a  little  out  on  the  arches  and  tending  to  spread 
forward  toward  the  first  pair  of  arches,  and  is,  of  course,  variable.  At  the  angles  between 
the  arches  the  color  is  often  heightened  and  very  distinct.  The  color  picture  illustrating 
the  red  floor  shows  a  well  developed  process  scarcely  prior  to  visible  swelling,  and  not 
the  very  earliest  flush  of  hyperplasia.  The  color  changes  rapidly  under  examination 
on  account  of  the  excitement  of  the  fish  due  to  removal  from  water  and  the  vigorous 
handling  necessary.  The  red  flush  pales  rapidly  under  these  conditions  and  often  almost 
disappears  in  less  than  a  minute,  due  to  the  inhibition  of  the  circulation  from  nervous 
shock,  the  area  taking  on  a  dirty  gray  color. 

The  red-floor  stage  is  not  sharply  demarcated  from  the  succeeding  stages.  It  pro- 
ceeds gradually  and  is  succeeded  by  or  merged  with  visible  tumor  formation,  the  color 
persisting  and  spreading  in  various  degrees  over  the  subsequent  swelling. 


CARCINOMA   OF  THE  THYROID   IN   SALMONOID   FISHES.  383 

Fish  which  are  without  any  clinical  evidence  of  thyroid  disease,  either  in  externally 
visible  swelling  or  the  inflamed  and  flushed  condition  of  the  floor  of  the  mouth,  are  for 
brevity  referred  to  in  this  report  as  clean  or  clinically  clean. 

It  is  the  increased  vascularity  associated  with  increased  thyroid  that  causes  the 
red  floor,  and  an  increased  amount  of  hyperemic  thyroid  tissue  of  normal  type  sometimes 
makes  a  visible  flush  on  the  floor  of  the  mouth  so  that  the  red  floor  is  not  an  absolute 
and  infallible  sign  of  thyroid  hyperplasia.  The  wild  brook  trout  held  in  confinement 
in  cement  tanks  and  fed  natural  food  showed  after  two  years  a  number  of  cases  of  red 
floors.  (See  table  vm.)  Microscopically  the  thyroid  was  considerably  increased  in 
amount  but  not  otherwise  definitely  changed  from  the  normal  type.  Likewise  the 
adult  Scotch  sea  trout  show  occasional  red  floors  referable  to  the  microscopical  condition 
of  colloid  goiter.  Such  cases  of  red  floors  are  evidently  to  be  separated  from  those  in 
which  the  flush  is  caused  by  the  early  stage  of  carcinoma. 

VISIBLE   TUMORS. 

Branchial  junction. — Whereas  evidence  of  beginning  growth  of  thyroid  tissue  in 
the  affected  fish  is  first  shown  by  a  more  or  less  distinct  reddening  of  the  floor  of  the 
mouth,  the  growth  of  tumor  tissue  in  the  spaces  about  the  aorta  and  in  the  muscular 
structure  of  the  isthmus  may  proceed  to  a  very  considerable  extent  before  the  growth 
gives  other  macroscopic  evidence  of  its  presence.  The  illustrations  of  visible  tumors 
in  the  literature  usually  depict  growths  appearing  at  the  branchial  junction.  Because 
of  the  resistance  offered  to  the  growth  of  the  tumor  by  the  bony  and  cartilaginous  struc- 
tures forming  the  floor  of  the  mouth,  it  is  natural  to  expect  that  the  region  at  the  junction 
of  the  first  pairs  of  gills  with  the  isthmus,  representing  the  line  of  least  resistance,  would 
be  the  first  and  most  frequent  site  of  the  visible  outgrowths.  This  median  region  we 
refer  to  as  the  branchial  junction. 

In  an  analysis  of  91  tumors  carefully  classified  (table  i),  we  find  that  the  branchial 
junction  alone  is  the  site  of  the  visible  tumors  in  but  4  cases,  but  where  the  growth  of 
tumor  tissue  is  sufficiently  extended  to  protrude  in  other  directions  it  is  found  to  be  the 
site  of  visible  outgrowths  in  combination  with  one  or  the  other,  in  67  cases.  The  branch- 
ial junction  is  therefore  one  of  the  most  common  sites  for  the  early  evidence  of  tumor 
growth.  In  many  cases  the  first  macroscopic  evidence  of  the  disease  is  found  in  the 
appearance  of  small  protrusions  with  smooth  surface,  of  rose  color,  often  not  larger 
than  a  grain  of  rice  or  smaller,  on  each  side  of  the  isthmus  exactly  at  the  branchial 
junction.  This  evidence  of  tumor  formation  is  almost  always  associated  with  the 
evidences  of  reddening  of  the  floor  of  the  mouth  and  means  that  the  available  space 
below  the  branchial  arches  and  about  the  aorta  is  filled  with  tumor  mass  and  that  the 
conditions  favoring  the  growth  downward  of  the  tumor  have  determined  its  first  pro- 
trusion in  this  direction.  Tumors  making  their  first  appearance  at  the  branchial  junction 
on  one  or  either  side  of  the  isthmus  may  rapidly  develop  into  large  growths  in  this  region. 
As  they  increase  in  size  they  become  more  readily  recognizable,  push  the  gill  covers 
apart  and  ultimately  present  themselves  as  obvious  growths  protruding  into  the  gill 
spaces  on  either  side. 


384  BULLETIN   OF  THE   BUREAU   OF   FISHERIES. 

In  the  diagrams  of  the  48  analyzed  tumors  here  presented,  great  irregularity  of  out- 
line, size  and  form  of  these  outgrowths  on  the  inferior  aspect  of  the  fish  may  be  easily 
studied.  The  freedom  afforded  by  the  spaces  between  the  gill  covers  and  the  isthmus 
permits  of  the  growths  of  tumors  of  enormous  size.  Figure  27  represents  a  2 -year-old 
brook  trout  with  a  tumor  of  such  magnitude  that  practically  the  entire  gill  space  is 
filled  by  one  tumor  mass,  which  has  pushed  the  isthmus  downward  and  practically  oc- 
cludes the  entire  gill  space.  In  some  cases  tumors  of  great  size  may  develop  in  such  a 
way  as  to  push  the  isthmus  to  one  side  and  present  the  appearance  of  a  unilateral  tumor. 
In  all  these  cases,  however,  the  tumor  tissue  is  found  to  extend  from  the  median  region 
about  the  aorta,  which  is  the  site  of  the  normal  thyroid  tissue  from  which  all  these 
tumors  spring.  Occasionally  tumors  extend  downward  and  make  their  first  appearance 
through  the  substance  of  the  isthmus,  indicating  the  exquisite  infiltrative  character 
of  the  growth,  and  in  one  instance,  the  first  macroscopic  evidence  of  tumor  (fig.  4)  was 
found  at  the  base  of  the  isthmus  in  the  solid  muscular  structure  of  the  breast  of  the  fish. 

Floor  of  the  mouth. — Although  the  lines  of  least  resistance  for  the  growth  of  tumor 
tissue  springing  from  the  thyroid  region  are  obviously  downward,  a  large  proportion 
of  all  tumors  give  evidence  of  their  existence  in  the  floor  of  the  mouth.  In  an  analysis 
of  91  fish  taken  at  random,  visible  evidence  of  tumor  growth  in  the  floor  of  the  mouth 
was  found  in  70  instances.  The  reddening  of  the  floor  of  the  mouth,  which  is  the  first 
evidence  of  tumor  growth,  is  replaced  by  infiltration  through  the  structures  of  the  floor 
of  the  mouth,  developing  either  by  uniform  bulging  upward  of  the  floor  or  the  protrusions 
of  masses  between  the  branchial  junctions ;  or  one  or  more  rounded  masses  of  large  dimen- 
sion may  become  prominent.  (Fig.  26  and  29.)  Not  infrequently,  besides  the  upheaval 
of  the  floor,  the  tumor  tissue  breaks  through  the  elastic  structure  of  the  underlying 
rnucosa  and  produces  minute  papillary  growths.  These  are  usually  of  shiny  appear- 
ance, small  or  rounded,  irregularly  shaped,  and  present  the  appearance  of  vegetations 
scattered  over  the  floor  of  the  mouth.  (Fig.  30.) 

Pit  tumors. — Early  in  our  investigations  Marsh  called  attention  to  the  fact  that  the 
jugular  pit  often  contained  a  tumor  which  was  entirely  independent  of  the  thyroid 
enlargement  originating  in  the  thyroid  region.  (Fig.  24.)  Of  the  91  tumors  analyzed, 
in  5  the  only  macroscopic  evidence  of  tumor  growth  was  in  the  jugular  pit.  In  combina- 
tion with  other  regions  the  jugular  pit  was  the  site  of  tumor  growth  in  20  other  examples, 
and  in  the  entire  91  it  was  the  site  of  tumor  growth  in  25.  As  has  been  shown  in  the 
chapter  on  embryology,  we  were  able  to  demonstrate  the  existence  of  deposits  of  normal 
thyroid  tissue  in  the  immediate  vicinity  of  this  so-called  jugular  pit.  The  frequency 
of  tumors  in  this  region  strongly  indicates  that  deposits  of  thyroid  in  this  region  are  not 
uncommon,  and  in  determining  the  limitation  of  distribution  of  the  thyroid  in  normal 
fish,  the  frequency  of  displacement  of  occasional  follicles  in  this  region  must  be  recog- 
nized. As  will  be  seen  from  the  diagrams,  the  jugular  pit  may  be  the  site  of  outgrowth 
of  tumor  tissue  of  very  considerable  extent,  and  of  various  forms.  They  are  usually 
subspherical,  or  hemispherical,  may  be  slightly  flattened  or  considerably  elongated, 
and  occasionally  vegetate  irregularly  and  take  on  bizarre  forms.  They  vary  greatly  in 
size,  from  bare  visibility  to  masses  having  a  diameter  of  17  millimeters  or  even  more. 


CARCINOMA   OF   THE   THYROID   IN   SAL,MONOID   FISHES. 
t 


385 


DIAGRAM  i.— Fish6i,  S.  fonlinalis,  length  20  cm.;  type  alveolar. 


DIAGRAM  2.— Fish  72,  S.  fontinalis,  length  26.5  cm.;  type  alveolar. 


DIAGRAM  3.— Fish  73,  S.  fontinalis,  length  22  cm.;  type  alveolar. 


DIAGRAM  4.— Fish  75-157,  S.  fontinalis,  length  26.4  cm.;  type  tubular. 


386 


BULLETIN   OF  THE   BUREAU   OF  FISHERIES. 

I 


DIAGRAM  5. — Fish  93.  rainbow,  length  38.5  cm.;  type  papillar. 


DIAGRAM  6. — Fish  93,  rainbow,  length  39  cm.;  type  alveolar. 


DIAGRAM  7. — Fish  94,  rainbow,  length  33  cm.;  type  papillar. 


DIAGRAM  8. — Fish  96,  S.  fontinalis,  length  25.3  cm.;  type  alveolar. 


CARCINOMA   OF   THE   THYROID   IN   SALMONOID   FISHES.  387 


DIAGRAM  9.— Fish  106,  S.  irideus,  length  25.5;  type  alveolar. 


DIAGRAM  10.— Fish  107,  S.  irideus.  length  34  cm.;  type  alveolar 


DIAGRAM  u.— Fish  108.  5.  irideus,  length  34  cm.;  type  alveolar. 


DIAGJIAM  is.— Fish  116,  S.  solar  sebago,  length  10.3  cm.;  type  papillar. 


388 


BULLETIN   OP  THE   BUREAU   OF  FISHERIES. 


DIAGRAM  13. — Fish  no,  S.  salar  sebago,  length  14.7  cm.;  type  alveolar. 


DIAGRAM  14. — Fish  124,  humpback,  length  14. 7  cm.;  type  alveolar. 


DIAGRAM  15. — Fish  135,  humpback,  length  14.8  cm.;  type  alveolar. 


c± 


DIAGRAM  16. — Fish  131,  Coregonus,  length  60  cm.;  type  sol'd. 


CARCINOMA   OF  THE   THYROID   IN   SAUtONOID   FISHES.  389 


DIAGRAM  17.— Fish  133,  humpback,  length  14.4001.;  type  alveolar. 


DIAGRAM  18. — Fish  139,  Salmo  hybrid,  length  10.7  cm.;  type  alveolar. 


DIAGRAM  19.— Fish  140,  Salmo  hybrid,  length  8.7  cm.;  type  solid. 


DIAGRAM  jo.— Fish  151.  5.  fonti.nalis.  length  11  cm.;  type  tubular. 


390 


BULLETIN   OF  THE  BUREAU   OF  FISHERIES. 


DIAGRAM  21. — Fish  152,  S.  fontinalis,  length  19  cm.;  type  tubular. 


DIAGRAM  22. — Fish  156,  S.  fontinalis,  length  18  cm.;  type  tubular. 


DIAGRAM  23. — Fish  172,  S.  fontinalis,  length  17  cm.;  type  solid. 


DIAGRAM  24. — Fish  174,  S.  fontinalis,  length  20  cm.;  type  papillar. 


CARCINOMA   OF  THE   THYROID   IN   SALMONOID   FISHES.  39! 


DIAGRAM  35.— Fish  181,  landlocked  salmon,  length  35  cm.;  type  alveolar. 


DIAGRAM  26. — Fish  183,  S.  fonlinalis,  length  15.9  cm.;  type  alveolar. 


DIAGRAM  27. — Fish  205,  hybrid,  length  17.6  cm.;  type  papillar. 


DIAGRAM  38.— Fish  208,  hybrid,  length  16  cm.;  type  papillar. 


392 


BUWJ3TIN   OF  THE   BUREAU  OF  FISHERIES. 


DIAGRAM  29. — Fish  209,  hybrid,  length  16.3  cm.;  type  papillar. 


DIAGRAM  30. — Fish  217,  S.  fontinalis,  length  9.9  on.;  type  alveolar. 


DIAGRAM  31. — Fish  101,  S.  fontinalis,  length  21.5  cm.;  type  papillar. 


DIAGRAM  32. — Fish  117,  S.  solar  sebago,  length  14.5  cm.;  type  papillar. 


CARCINOMA   OF   THE   THYROID   IN   SALMONOID   FISHES.  393 


DIAGRAM  33.— Fish  121,  O.  gorbuscha,  length  13.5  cm.;  type  solid. 


DIAGRAM  34.— Fish  149,  S.  fontinalis,  length  23  cm. ;  type  alveolar. 


DIAGRAM  33.— Fish  160.  S.  fontinalis,  length  21.9  cm.;  type  alveolar. 


DIAGRAM  36.— Fish  175.  S.  fontinalis,  length  14.5  cm- 1  type  alveolar. 
8207°— 14 3 


394 


BULLETIN  OP  THE   BUREAU  OF   FISHERIES. 


DIAGRAM  37. — Fish  100,  S.  fontinalis,  length  24  cm.;  type  papillar. 


DIAGRAM  38. — Fish  103,  S.  fontinalis,  length  24  cm.;  type  papillar. 


DIAGRAM  39. — Fish  122,  humpback,  length  14.5  cm.;  type  solid. 


DIAGRAM  40. — Fish  112,  S.  salar  sebago,  length  13.5  cm.;  type  alveolar. 


CARCINOMA  OF  THE  THYROID  IN   SALMONOID   FISHES. 


395 


DIAGRAM  41.— Fish  150,  S.  fonlinalis,  length  16.5  cm.;  type  papillar. 


DIAGRAM  42. — Fish  153,  S.  fontinalis,  length  24.3  cm.;  type  alveolar. 


DIAGRAM  43-— Fish  154,  S.  fontinalis,  length  18.7  cm.;  type  alveolar. 


DIAGRAM  44.— Fish  135.  S.  iontinalis,  length  24  cm.;  type  alveolar. 


396 


BULLETIN   OF  THE   BUREAU   OF   FISHERIES. 


DIAGRAM  45. — Fish  158,  5.  fontinalis,  length  18.6  cm.;  type  alveolar. 


DIAGRAM  46. — Fish  159,  5.  fontinalis,  length  21.6  cm.;  type  alveolar. 


DIAGRAM  47. — Fish  162,  S.  fontinalis,  length  23  cm.;  type  mixed. 


DIAGRAM  48. — Fish  169,  S.  fontinalis,  length  23  cm.;  type  alveolar. 


CARCINOMA   OF  THE  THYROID   IN   SALMONOID   FISHES. 


397 


From  their  position  they  are  subject  to  mechanical  erosion  on  their  ventral  surface. 
When  well  developed  the  tumor  usually  fills  and  completely  obliterates  the  pit.  When 
the  latter  is  not  the  seat  of  tumor  growth,  it  is  sometimes  completely  everted  by  the 
pressure  of  the  tumor  from  the  main  thyroid  region,  and  almost  all  trace  of  it  lost,  the 
surface  of  the  skin  being  stretched  smooth  in  this  region. 

TABLE  I. — CLASSIFICATION  OP  VISIBLE  TUMORS  BY  LOCATION. 


Visible  tumor  presenting  at  — 

Number. 

Visible  tumor  presenting  at  — 

Number. 

Branchial  junction  

Pit  and  floor 

Pit  

Right  gill  region  

Gill  region  and  floor 

Left  gill  region  

i 

Gill  region  and  pit 

Both  gill  regions  

6 

Pit,  gill  region,  and  floor 

Floor                          .          

Branchial  junction  and  floor  

6 

Pit  and  branchial  junction 

Branchial  junction  and  gill  

4 

Branchial  junction,  pit,  floor 

Gill  region  and  floor  

27 

Pit  and  gill  region  

Visible  tumors  examined 


HISTOLOGY. 
EARLY  STAGE. 

Under  "Simple  Hyperplasia"  we  have  presented  evidence  which  we  believe  indicates 
that  there  occurs  in  wild  and  domesticated  fish  a  type  of  simple  hyperplasia  which  leads 
to  colloid  goiter.  The  first  changes  in  the  epithelium  in  any  form  of  hyperplasia, 
whether  simple  or  malignant,  would  be  of  the  same  character  and  thus  indistinguishable 
one  from  the  other.  The  progress  of  carcinoma  of  the  thyroid  in  the  vSalmonidae  may 
for  convenience  be  divided  into  three  periods:  That  in  which  only  microscopic  evidence 
of  hyperplasia  is  discernible ;  the  stage  in  which  the  growth  of  tissue  extends  sufficiently 
to  produce  hyperasmic  changes  visible  in  the  floor  of  the  mouth — i.  e.,  red  floor;  and  then 
the  period  of  visible  tumors.  Histologically  no  line  of  demarcation  is  possible  between 
these  various  stages.  Neither  is  it  possible  to  distinguish  the  very  first  changes  in  the 
epithelium  at  the  onset  of  this  disease  from  simple  hyperplasia  leading  to  colloid  goiter 
as  we  have  observed  it  in  the  Scotch  sea  trout  which  have  proven  immune  to  carcinoma 
of  the  thyroid. 

Normal  thyroid  tissue  in  the  Salmonidae  is  composed  of  isolated  follicles  lined  with 
flattened  epithelium  containing  colloid.  The  follicles  are  distributed  as  shown  about 
the  aorta  in  the  loose  connective  tissue. 

The  first  indication  of  the  disease  is  found  in  the  hypertrophy  of  individual  cells ; 
in  a  given  follicle  usually  the  change  affects  one  or  two  adjacent  follicles,  or  the  only 
evidence  of  the  beginning  of  the  disease  is  found  in  a  small  group  of  follicles  lined  with 
cubical  or  columnar  epithelium  in  which  the  colloid  is  greatly  reduced  or  entirely  absent. 
Hyperemia  of  the  vessels  of  the  stroma  is  usually  present.  In  our  experiments  with 
wild  Wisconsin  brook  trout,  in  which  fish  of  varying  size  and  age  were  taken  from  the 
wilderness  and  placed  in  the  waters  of  the  Craig  Brook  hatchery,  the  first  evidence  of 


398  BULLETIN   OF  THE   BUREAU  OF  FISHERIES. 

the  disease  was  found  in  changes  like  those  above  described  and  affected  individual  or 
small  groups  of  follicles  lying  adjacent  to  the  large  arteries.  (Fig.  40.)  One  or  two 
selected  protocols  of  fish  in  which  the  disease  was  experimentally  induced  and  properly 
controlled  show  that  the  action  of  the  agent  causing  the  disease  is  clearly  focal.  Budding 
of  the  wall  of  the  follicle  is  early  in  evidence,  presenting  an  appearance  much  like  that 
found  in  the  embryo,  where  the  formation  of  secondary  follicles  is  in  progress.  But 
here,  instead  of  this  budding,  resulting  in  the  formation  of  isolated  follicles  of  the  usual 
type,  we  have  the  formation  of  irregular  groups  of  cells,  tubules,  and  groups  of  alveoli 
of  irregular  shape,  lined  with  columnar  epithelium.  In  this  way  new  follicles  are  formed 
(fig.  36).  From  the  very  beginning  there  is  a  tendency  to  infiltration  in  the  surrounding 
structures.  (Fig.  34.) 

The  fact  that  the  gland  of  the  teleost  is  not  encapsulated  was  first  offered  by 
Gudernatsch  as  an  explanation  for  the  infiltrative  character  of  these  growths.  This  is 
undoubtedly  true  so  far  as  the  extension  of  formed  follicles  between  the  muscle  bundles 
and  into  the  tissues  adjacent  to  the  normal  deposits  of  thyroid  tissue  is  concerned.  In 
this  way,  with  the  inauguration  of  the  disease,  we  find  the  growth  of  thyroid  tissue 
into  the  surrounding  structure.  Such  growth  follows  in  the  first  instance  the  lines  of 
least  resistance  and  is  in  our  opinion  quite  distinct  from  the  phenomenon  of  the  infiltra- 
tion of  adjacent  cell  structures  by  individual  cells — a  phenomenon  which  is  frequently 
found  with  the  very  first  evidence  of  the  disease.  The  cells  of  the  alveoli  in  this  stage 
have  changed  from  flattened  to  high  columnar,  with  deeply  staining  protoplasm,  basilar 
nuclei  often  vesicular  and  frequently  with  many  karyokinetic  figures.  Where  the  follicles 
have  simply  grown  between  the  muscle  bundles  or  against  opposing  structures,  such  as 
bone  and  cartilage,  they  are  frequently  flattened,  usually  of  small  size,  and  closely 
grouped.  Where  the  follicles  are  broken  through,  and  groups  of  individual  cells  infiltrate 
the  surrounding  structures,  there  is  frequently  marked  proliferation  of  the  interstitial 
connective  tissue.  Even  in  the  early  stages  great  variation  in  the  arrangement  of  the 
cells  is  apparent.  They  form  long,  narrow  tubules,  the  alveoli  more  or  less  irregular 
in  shape,  with  solid  masses  of  cells  and  large  irregular  spaces.  The  follicles  may  or  may 
not  contain  colloid.  In  the  early  stage  there  is  generally  a  marked  diminution  in  colloid. 
(Fig-  36.) 

RED-FLOOR   STAGE. 

In  this  stage  the  extent  of  proliferating  thyroid  is  such  as  to  be  visible  as  a  slight 
flush  on  the  floor  of  the  mouth.  Histologically  the  spaces  surrounding  the  vessels 
are  filled  with  tumor  tissue.  Bone,  cartilage,  and  muscle  are  invaded,  and  the  tumor 
tissue  extends  toward  the  gill  arches  and  backward  toward  the  heart.  A  characteristic 
of  this  stage  is  that  the  tumor  tissue  does  not  seek  the  paths  of  least  resistance,  but 
infiltrates  in  other  directions.  (Fig.  37.)  The  arrangement  is  tubular  or  alveolar  in 
most  instances;  the  epithelium  is  high  and  deeply  staining.  Only  occasional  follicles 
with  colloid  are  encountered.  There  is  a  well-defined  connective  tissue  reticulum. 
Karyokinetic  figures  are  numerous  and  are  found  in  most  tumors.  (Fig.  35  and  36.) 


CARCINOMA   OF  THE   THYROID   IN   SALMONOID   FISHES.  399 

VISIBLE   TUMOR    STAGE — STRUCTURAL   TYPES. 

In  the  larger  tumors  one  finds  a  remarkable  variation  in  the  histologic  picture. 
The  fundamental  types  may  be  divided  into  four — alveolar,  papillar,  tubular,  and  solid. 
In  occasional  tumors  one  of  these  three  types  definitely  predominates.  In  the  100 
tumors  selected  for  study  these  types  occur  in  the  following  proportions: 


Types. 

Per  cent. 

Fig.  No. 

Alveolar.  .  .         

S6 

Papillar  

61 

Solid  

Tubular  

•s 

Mixed.  .  . 

38 

One  is  struck,  however,  in  the  study  of  these  large  infiltrating  tumors,  with  the 
remarkable  variety  of  formation  to  be  found  in  various  regions.  One  may  find  in  a 
single  tumor  areas  which  may  be  placed  under  any  one  of  the  designations  given.  The 
action  of  the  stimulus  upon  the  thyroid  tissue  in  these  tumors  appears  not  only  to  work 
irregularly,  as  will  be  shown  by  the  advent  of  nodules  of  active  proliferation  and  areas 
simulating  hyperplasia,  but  appears  to  throw  the  entire  thyroid  tissue  into  such  a  riot 
of  proliferation  that  a  definite  type  for  the  entire  tumor  is  seldom  accomplished.  The 
epithelial  cells  forming  the  tumor  present  the  greatest  possible  variety  of  form  and  size. 
The  nuclei  are  usually  vesicular,  in  entire  areas  of  a  tumor  the  cells  may  present  a  typical 
spindle  form,  thus  simulating  sarcoma,  and  in  some  instances  areas  of  the  tumor  are 
made  up  of  a  background  of  spindle  cell  tissue,  through  which  are  scattered  small  but 
definite  alveoli  containing  colloid.  (Fig.  38.) 

In  such  a  tumor  we  have  a  picture  analogous  to  the  so-called  mixed  tumor  of  the 
thyroid  encountered  in  man.  Occasionally  tumors  may  be  met  in  which  a  large  propor- 
tion of  the  tumor  is  made  up  of  large  alveoli  packed  with  solid  masses  of  large  cells, 
deeply  staining  protoplasm  and  vesicular  nuclei,  and  frequent  karyokinetic  figures,  pre- 
senting the  picture  of  proliferating  struma.  (Langhans.)  (Fig.  39.) 

Again,  the  general  predominating  type  of  a  tumor  may  be  distinctly  papillary,  in 
which  large  vegetations  covered  with  columnar  epithelium  and  deeply  stained  nuclei 
are  found  projecting  into  irregular  spaces,  usually  free  from  colloid.  The  tendency 
to  papillary  formation  may  be  found  in  almost  all  of  these  tumors.  Occasionally  these 
papilliform  areas  are  of  nodular  form,  in  which  case  the  cells  forming  the  papillary  nodule 
are  more  deeply  stained  than  the  surrounding  tubular  or  alveolar  type,  which  gives 
them  a  distinct  focal  character.  (Fig.  45.)  This  marked  tendency  to  focal  or  nodular 
development  within  the  tumors  occasionally  produces  growths  in  which  we  have  a  large 
mass  of  tubulo-alveolar  structure,  with  nodules  of  solid,  closely  packed  areas  of  intensive 
proliferation.  In  figure  40  we  have  a  low-power  picture  of  such  a  tumor.  The  tumor 
mass  involves  the  entire  area  between  the  base  of  the  tongue  and  the  pericardial  space  and 
extends  between  the  arches  to  the  floor  of  the  mouth,  where  it  projects  in  a  series  of 
large  protrusions,  has  pushed  down  the  muscular  structure  of  the  isthmus,  protrudes  in 


400  BULLETIN   OF  THE   BUREAU  OP  FISHERIES. 

the  median  line  at  the  branchial  junction  and  extends  forward  into  the  areolar  tissue  at 
the  base  of  the  tongue,  and  presents  visible  evidence  of  erosion  of  the  large  mass  of  carti- 
lage at  the  base  of  the  tongue.  The  superior,  anterior,  and  protruding  posterior  portions 
of  this  tumor  are  composed  of  a  network  of  large  alveoli,  free  from  colloid,  in  which  are 
embedded  a  number  of  dense  nodular  growths.  One  of  these  protrudes  into  the  floor 
of  the  mouth,  a  group  of  larger  ones  forms  the  central  portion  of  the  tumor,  and  one  or 
two  small  ones  protrude  into  the  anterior  portion  of  the  alveolar  structure. 

Here  we  have  plainly  a  distinct  focal  evidence  of  proliferation  of  a  much  more 
*  intense  type  than  that  involving  the  surrounding  alveolar  tissue  growth.  The  small 
anterior  nodule  is  found  under  high  power  to  be  composed  almost  exclusively  (fig.  41) 
of  closely  packed  spindle  and  oval  cells  with  deeply  staining  nuclei  in  which  the  merest 
suggestion  of  an  attempt  at  alveolar  arrangement  in  some  of  the  cell  groups  may  be 
traced.  In  the  distinct  nodule  lying  in  the  floor  of  the  mouth  the  alveolar  structure 
is  more  apparent,  and  figure  42  shows  a  small,  distinct  nodule  of  adenomatous  type. 
The  margins  of  these  more  or  less  solid  nodules  in  this  tumor  gradually  merge  into 
the  loose  alveolar  structure  forming  the  remainder  of  the  tumor.  In  some  tumors, 
however,  we  have  found  small  nodules  of  closely  packed  alveoli,  the  cells  of  which  stain 
deeply,  with  closely  packed,  deeply  staining  nuclei,  the  nodule  embedded  in  a  reticulum 
of  more  open  alveolar  structure,  the  cells  of  which  are  not  in  so  active  a  state  of  prolifera- 
tion and  do  not  stain  so  deeply.  In  many  of  these  nodules  expansive  growth  is  evidenced 
by  compression  and  displacement  of  the  alveoli  of  the  tumor  tissue  surrounding  the 
nodule.  (Fig.  43.) 

INFILTRATION. 

In  another  aspect  of  the  nodule  one  finds  definite  evidence  of  infiltration  of  sur- 
rounding thyroid  tumor  tissue  by  individual  alveoli  of  the  more  malignant  type.  (Fig. 
44.)  We  have  here  definite  evidence  of  infiltration  of  thyroid  tissue  by  a  nodule  of  malig- 
nant degeneration  of  more  active  type.  The  importance  of  this  finding  is  that  the 
infiltration  in  this  instance  does  not  deal  with  anatomical  landmarks  or  adjacent  struc- 
tures but  represents  a  true  infiltration,  by  a  more  malignant  and  rapidly  growing  portion 
of  the  thyroid  tissue,  of  surrounding  thyroid  structure. 

A  nodular  development  in  the  tumors  indicates  a  more  intense  focal  action  of  the 
stimulus  causing  these  tumors.  It  has  been  suggested  that  proliferation  of  the  thyroid 
in  these  growths  in  the  Salmonidse  is  due  to  a  reaction  of  the  tissue  to  ^physiological 
demands.  A  marked  characteristic  of  physiological  hyperplasia  is  the  uniformity  with 
which  the  entire  organ  is  affected.  One  of  the  most  prominent  characteristics  of  these 
growths  in  the  thyroid  in  the  Salmonidae  is  intensive  local  stimulation,  which  leads  not 
only  to  nodules  within  the  tumor  masses,  but  gives  the  visible  growth  a  marked  lobulated 
appearance.  If  these  tumors  represented  a  response  to  physiological  demands,  we 
should  expect  a  more  uniform  character  of  the  hyperplastic  tissue.  We  should  expect 
all  of  the  thyroid  tissue  to  be  affected.  In  this  connection  the  section  of  fish  158  is 
significant.  Here  we  have  an  extensive  tumor  (diagram  45,  p.  36)  involving  the  entire 
region  between  the  isthmus  and  the  floor  of  the  mouth,  appearing  at  the  branchial 


CARCINOMA   OF  THE   THYROID   IN   SALMONOID   FISHES.  4OI 

junction  and  in  the  gill  spaces  on  both  sides,  protruding  between  the  first  and  second 
branchial  arches,  and  penetrating  the  floor  of  the  mouth  in  the  median  line  at  the  junction 
between  the  second  and  third  branchial  arches. 

Microscopically,  this  extensive  growth  is  found  to  infiltrate  the  surrounding  struc- 
tures, bone,  cartilage,  and  muscle.  It  may  be  classified  as  alveolo-tubular  type.  In 
many  regions  it  presents  a  characteristic  solid  structure.  Only  in  occasional  areas  do 
a  few  follicles  contain  poorly  staining  colloid.  In  the  region  of  the  third  branchial  arch 
is  found  a  cross  section  of  bone,  in  the  lumen  of  which  is  a  group  of  thyroid  follicles  of 
strictly  normal  appearance.  (Fig.  47.)  The  follicles  are  of  the  usual  size  filled  with 
homogeneously  and  deeply  staining  colloid,  the  epithelium  is  flattened,  protoplasm 
small  in  amount,  the  nuclei  stain  deeply  and  homogeneously.  A  study  of  the  preceding 
and  succeeding  serial  sections  fails  to  show  any  opening  through  the  wall  of  bone.  The 
tumor  tissue  is  in  immediate  contact  with  the  shell  of  bone  for  a  considerable  extent  of 
its  circumference,  the  remainder  is  covered  with  periosteum  and  dense  connective  tissue. 

The  significance  of  this  finding  is  that  here  we  have  a  large  tumor  of  tubulo-alveolo- 
solid  type  infiltrating  the  surrounding  structures,  while  lying  within  the  medullary 
space  of  the  bone  structure  and  included  in  the  tumor  tissue  is  a  deposit  of  normal 
thyroid  tissue  which  by  its  appearance,  and  the  presence  of  deeply  stainable  colloid, 
must  be  in  physiological  continuity  with  the  metabolism  of  the  fish.  That  the  deposit 
of  normal  thyroid  within  the  bone  has  remained  unaltered  because  it  was  protected  from 
an  agent  working  from  without  by  being  inclosed  within  the  bone  is  probable,  but  no  less 
important  is  the  fact  that  it  shows  clearly  that  portions  of  the  thyroid  structure  in  the 
Salmonidae  may  undergo  malignant  change,  while  other  portions  of  the  thyroid  tissue 
remain  strictly  normal  in  appearance  and  retain  their  physiological  function  until,  it 
may  be  said,  as  this  tumor  was  very  advanced,  the  last  stages  of  the  disease. 

A  great  deal  has  been  said  about  the  significance  of  the  capsule  of  the  thyroid  in 
mammals.  Here  the  evidence  of  malignancy  consists  in  a  breaking  through  the  capsule 
and  infiltration  of  the  surrounding  structures.  As  the  thyroid  structure  of  the  teleost 
has  no  capsule,  such  a  criterion  can  not  be  applied,  and  some  have  ascribed  the  infil- 
trative  characteristics  of  these  tumors  to  the  isolated  character  of  the  follicles  and  lack 
of  a  delimiting  capsule.  One  of  the  best  evidences  of  malignancy  in  the  mammalian 
thyroid  is  the  development  of  isolated  nodules  of  malignant  character  within  the  struc- 
ture of  an  enlarged  thyroid,  and  here  the  evidence  of  infiltration  has  not  to  do  with  a 
capsule,  but  the  infiltration  of  surrounding  thyroid  structure.  A  determination  of 
exactly  analogous  conditions  in  our  tumors  indicates  that  we  have  in  the  proliferation 
of  the  tumor  tissue  in  the  Salmonidae  an  expression  of  genuine  malignancy. 

Infiltration  of  bone  and  cartilage. — The  growth  of  these  extensive  tumors  naturally 
leads  to  the  erosion  and  destruction  of  cartilage  and  bone.  The  mere  presence  of 
thyroid  tissue  within  the  bone  spaces  of  the  branchial  arches  is  in  itself  of  no  signifi- 
cance. Deposits  of  normal  thyroid  tissue  are  often  encountered  in  the  open  spaces  of 
both  bone  and  cartilage.  The  shape  of  the  bony  and  cartilaginous  structure  in  the 
floor  of  the  mouth  in  the  teleost  is  frequently  such  that  the  thyroid  tissue  grows  in 
through  small  openings  in  the  base  of  the  arches.  In  many  instances,  however,  we 


402  BULLETIN  OF  THE  BUREAU  OF  FISHERIES. 

find  total  destruction  of  cartilage  and  bone  and  marked  evidences  of  infiltration  of  the 
bony  and  cartilaginous  structures  by  individual  cells  and  groups  of  cells.  (Fig.  48 
and  49.) 

Infiltration  of  vessel  -walls,, — Genuine  infiltration  of  vessel  walls  will  serve  much  the 
same  purpose  as  infiltration  of  the  capsule  in  mammals,  as  deposits  of  thyroid  tissue 
within  the  media  of  the  larger  vessels  has  never  been  encountered.  Figures  33  and 
50  show  a  section  of  the  aortic  wall  stained  with  orcein,  in  which  the  elastic  lamellae 
of  the  media  are  split  up  and  spread  out  into  the  adjoining  tumor  mass  as  the  result 
of  the  penetration  between  the  elastic  lamellae  of  the  alveoli  of  an  infiltrating  tumor. 
The  aortic  wall  at  this  point  is  reduced  to  about  half  the  thickness  of  the  uninfiltrated 
remainder  of  the  circumference.  We  have  here  genuine  infiltration  of  the  media  of  the 
aorta. 

Infiltration  of  muscle. — Besides  the  growth  of  the  alveoli  of  tumors  between  the 
muscle  bundles  (fig.  37) ,  we  frequently  encounter  infiltration  of  individual  muscles  cells 
by  tumor  cells.  In  these  cases  the  sarcolemma  sheath  is  broken  through  and  we  find 
the  isolated  cells  of  the  tumor  displacing  the  muscle  fiber.  (Fig.  51.)  The  tumor  tissue 
in  many  instances  has  lost  its  alveolar  structure,  the  cells  being  closely  packed  together 
without  definite  form.  There  are  many  instances  of  genuine  infiltration  by  individuals 
or  groups  of  cells  in  the  muscle  fibers. 

Infiltration  of  the  skin. — This  is  usually  best  observed  in  the  floor  of  the  mouth. 
It  has  been  suggested  that  the  breaking  through  of  tumor  masses  of  the  outer  integu- 
ment was  due  largely  to  pressure,  that  the  epidermis  became  greatly  thinned  and  ulti- 
mately eroded.  This  is  in  many  instances  true  where  large  masses  of  tumor  protrude 
into  the  floor  of  the  mouth  or  where  protuberant  growths  extend  downward  or  outward. 
In  the  floor  of  the  mouth,  however,  we  frequently  find  that  the  elastic  structure  of  the 
skin  and  the  epithelial  strata  overlying  it  are  punctured  by  small  vegetations.  Figures 
31  and  32  show  such  growths.  Frequently  growths  penetrating  the  floor  of  the  mouth 
will  be  found  to  have  split  up  and  destroyed  the  elastic  structure  of  the  epidermis  without 
any  appreciable  thinning  whatsoever,  the  entire  thickness  of  the  elastic  structure  sud- 
denly disintegrating  without  any  evidence  of  stretching  or  thinning.  (Fig.  46.)  It 
is  therefore  evident  that  besides  expansive  growth,  carcinoma  of  the  thyroid  in  the  Sal- 
monidae  presents  indisputable  evidence  of  genuine  infiltration,  such  as  we  encounter 
in  malignant  growths  in  other  species. 

% 

OTHER   OBSERVATIONS. 

In  1905,  L.  Pick  published  a  comprehensive  article  entitled  "Carcinoma  of  the 
Thyroid  in  the  Salmonidae, "  with  15  illustrations.  It  is  by  all  means  the  most  important 
publication  on  this  subject  dealing  with  the  histology  of  these  tumors.  Pick's  material 
consisted  of  10  brook  trout  obtained  from  a  hatchery,  we  are  led  to  believe,  in  the  United 
States.  He  illustrates  five  of  these  fish,  one  of  which  exhibited  a  large  infiltrating 
tumor  involving  the  entire  region  below  the  floor  of  the  mouth  and  the  muscular  struc- 
ture of  the  isthmus  (Pick,  1905,  fig.  i).  Figure  3  shows  a  small  tumor  at  the  branchial 


CARCINOMA   OF   THE   THYROID   IN   SALMONOID   FISHES.  403 

junction.  Figure  4,  a  view  from  above  downward,  shows  a  vegetating  tumor  in  the 
floor  of  the  mouth.  Figure  2  illustrates  an  isolated  tumor  in  the  jugular  pit,  and  figure 
5  a  tumor  in  the  jugular  pit  and  one  at  the  branchial  junction. 

Pick's  paper  is  particularly  excellent  in  the  thoroughness  with  which  he  deals  with 
the  histology  of  these  tumors.  In  fish  i,  with  the  large  infiltrating  tumor  in  the  floor 
of  the  mouth,  he  recognizes  the  variegated  character  of  the  epithelial  structure,  distin- 
guishing an  adenomatous  portion  and  a  follicular  portion,  both  of  which  he  closely 
describes.  He  points  out  the  absence  of  any  evidence  of  a  capsule  and  describes  fully 
and  accurately  the  infiltrating  character  of  the  tumor  tissue.  He  notes  the  extension 
of  the  tumor  in  the  lymph  spaces  of  the  neighboring  muscular  fascia,  which  he  describes 
as  being  destroyed  by  the  infiltration.  Strands  of  tumor  cells  which  widen  into  follicles 
invade  the  lymph  spaces  of  the  adventitia  of  the  aorta.  He  describes  the  invasion  and 
breaking  up  of  the  tendon  of  insertion  of  the  muscle  of  the  isthmus.  The  epithelium 
of  the  tumor  invades  the  loose  submucous  fatty  tissue,  and  the  spaces  of  the  dense  con- 
nective tissue  and  the  tunica  propria  of  the  mucosa  of  the  floor  of  the  mouth.  Not  only 
are  the  softer  tissues  invaded,  but  he  finds  that  both  cartilage  and  bone  are  destroyed. 
This  is  accomplished  by  the  tumor  surrounding  the  bone  growing  into  the  various  infold- 
ings  of  the  branchial  arches  and  the  cavities  of  the  bone,  opening  up  the  capsule  of  the 
cartilage,  and  invasion  of  the  cartilage  tissue  proper,  infiltration  between  the  periosteum 
and  the  bone,  thus  leading  to  the  death  of  fragments  of  bone  and  the  formation  of 
sequestra  which  through  the  process  of  decalcification  and  fibrillation  disintegrate. 

In  his  description  of  fish  3  he  shows,  in  figure  8,  the  invasion  of  the  mucosa  of  the 
floor  of  the  mouth  by  papillary  outgrowths  which,  in  the  instance  illustrated,  shows 
the  formation  of  small  cystlike  alveoli  within  the  epithelium  of  the  mucosa.  In  fish  5 
he  describes  and  in  figure  9  illustrates  the  solid  type  of  tumor;  in  figure  10  is  shown 
the  polymorphic  nature  of  the  cells  of  this  tumor.  In  fish  7  he  describes  portions  of 
tumor  with  large  cystic  alveoli,  flattened  single  layer  of  epithelium  and  stainable  colloid 
(struma  thyreoidea  parenchymatosa  colloides).  In  fish  8  the  papillary  type  of  growth 
is  described. 

Pick  concludes  that  these  tumors  are  undoubtedly  infiltrating  epithelial  neoplasms, 
malignant  epithelioma,  or  in  the  general  sense  of  Orth's  definition,  carcinoma.  He 
points  out  that  the  diffuse  deposit  of  thyroid  tissue  does  not  necessarily  become  diseased 
in  toto;  in  fact,  that  it  is  more  often  affected  at  various  points,  that  the  growths  are 
pluri-centric.  He  thinks  that  these  centers  of  growth  originate  simultaneously  or  at 
different  times,  that  they  may  grow  more  or  less  uniformly  and  that  in  some  cases 
outlying  extensions  of  thyroid  tissue  become  involved,  these  facts  explaining  the  remark- 
able variety  of  form  of  the  tumors,  the  directions  in  which  they  infiltrate,  whether 
upward  into  the  floor  of  the  mouth  or  laterally  into  the  gill  spaces,  and  the  fact  that  they 
may  be  bilaterally  symmetrical  or  unsymmetrical. 

He  points  out  the  absence  of  a  capsule  in  any  of  the  tumor  fish.  He  recognizes 
that  several  of  his  tumors  have  retained  very  definitely  the  thyroid  structure  and  speaks 
of  these  as  presenting  the  character  of  parenchymatous  struma,  although  in  such  tumors 
the  infiltrative  character  and  destruction  may  be  very  great,  these  being  tumors  of 


404  BULLETIN   OF  THE  BUREAU  OF  FISHERIES. 

homotypic  character;  and  that  in  others  the  great  variation  in  size  of  cells  and  marked 
deviation  from  the  organal  type  produce  tumors  of  heterotypic  character. 

IMPLANTATIONS  AND  METASTASES. 

i 
It  is  obviously  of  the  greatest  importance  in  a  neoplasm  of  the  character  of  the 

carcinoma  of  the  thyroid  in  the  Salmonidae  to  determine  whether  or  not  metastases 
or  possibly  implantation  may  occur.  Although  infiltrative  growth  is  and  will  always 
remain  one  of  the  best  evidences  of  malignancy,  yet  in  the  last  analysis  a  true  neoplasm 
must  present  some  evidence  of  metastasis  formation  or  the  development  of  implants. 
The  experimental  study  of  cancer  has  placed  a  new  significance  upon  the  importance  of 
transplantability.  Experimental  results  with  mouse  and  rat  tumors  clearly  indicate 
that  metastasis  formation  may  be  controlled  or  at  least  influenced  by  concomitant 
immunity,  and  as  the  immune  phenomena  are  more  outspoken  in  the  more  virulent 
types  of  cancer,  it  is  not  surprising  that  a  neoplasm  involving  a  vital  organ  like  the 
thyroid,  through  its  early  infiltrative  growth  involving  vital  structures,  might  prove 
the  determining  factor  in  the  early  carrying  off  of  the  individual  and  thus  the  life  of  the 
affected  fish  might  not  extend  into  the  period  in  which  metastasis  formation  more 
frequently  occurs. 

The  rarity  of  the  occurrence  of  metastases  in  any  given  group  of  tumors  may  well  be 
expected.  In  such  a  case  one  or  two  instances  may  serve  the  purpose  of  definitely 
fixing  the  nature  of  the  neoplasm.  The  occurrence  of  metastasis  in  the  thyroid  carci- 
nomata  of  fish  is  certainly  rare.  The  circulation  of  the  fish  is  not  well  adapted  to  the 
transportation  of  cells.  The  region  in  which  transported  cells  would  most  easily  obtain 
lodgment  would  be  in  the  bifurcations  of  the  vessels  of  the  branchial  arches,  and  it  is  a 
common  occurrence  to  find  isolated  growths  well  away  from  the  median  line  on  these 
structures,  but  as  deposits  of  thyroid  tissue  are  located  immediately  about  the  aorta 
many  of  these  growths  will  be  found  to  be  simply  outgrowths  from  the  primary  mass  in 
the  median  line.  Some  of  them  are,  however,  so  widely  displaced  from  the  median  mass 
that  they  may  be  looked  upon  as  regional  metastases  in  which  the  transport  of  cells 
would  have  to  be  accomplished  through  the  lymph  channels.  It  may  be  said  that 
growths  in  this  region,  however,  are  not  competent  to  determine  the  question  of  true 
metastasis  formation  from  transport  of  cells.  A  region  already  referred  to  and  one  in 
which  the  development  of  tumors  is  very  frequent,  occurring  in  not  less  than  25  per 
cent  of  the  studied  cases,  is  the  jugular  pit.  The  explanation  for  these  growths  is, 
however,  found  in  the  frequent  presence  of  misplaced  thyroid  tissue.  The  origin  of 
these  deposits  has  been  clearly  traced  and  adequately  explained. 

Early  in  our  observations  we  noted  that  occasional  growths  upon  the  tip  of  the  lower 
jaw  were  to  be  seen.  (Fig.  28.)  This  region  in  the  fish  is  one  peculiarly  exposed  to 
injury.  The  fish  confined  in  tanks  almost  certainly  run  into  the  sides  of  the  tanks  or 
the  screens  and  injure  the  epidermis  at  this  point.  These  growths  at  the  apex  of  the 
lower  jaw  might  be  explained  by  the  presence  of  unusual  deposits  of  thyroid  tissue  at 
this  point.  We  have  examined,  by  serial  section,  this  region  of  the  lower  jaw  in  25 
fish,  and  have  never  found  any  trace  of  normal  thyroid  in  this  location.  Furthermore, 


CARCINOMA   OP  THE  THYROID  IN   SALMONOID   FISHES.  405 

a  careful  study  of  the  development  of  the  thyroid  in  the  embryo  gives  no  indication 
whatever  of  the  likelihood  of  thyroid  tissue  being  deposited  at  this  point,  and  in  the  careful 
survey  of  the  distribution  of  the  thyroid  in  wild  fish  we  have  never  seen  any  deposits  of 
normal  thyroid  tissue  even  so  far  forward  as  the  base  of  the  tongue.  We  must,  there- 
fore, conclude  that  there  is  no  evidence  that  thyroid  tissue  is  ever  laid  down  in  this 
locality. 

The  anatomical  structure  at  this  point  is  also  very  unfavorable  for  the  deposit  of 
normal  thyroid  tissue.  The  symphysis  of  the  dentaries  here  is  covered  only  by  the  peri- 
osteum, a  thin  layer  of  dense  subcutaneous  connective  tissue  upon  which  rests  directly 
the  elastic  structure  and  the  epidermis  of  the  outer  covering.  In  fish  6 1,  diagram  i, 
we  find  an  extensive  growth  of  thyroid  tumor  springing  from  the  apex  of  the  lower  jaw, 
entirely  distinct  and  separate  from  the  usual  growth  of  tumor  about  the  aorta  and 
extending  up  into  the  floor  of  the  mouth.  A  microscopic  examination  of  the  growth  of 
the  tip  of  the  jaw  and  the  primary  growth  in  the  substance  of  the  isthmus  shows  that 
they  present  much  the  same  appearance,  being  both  alveolar  in  type  and  many  of  the 
alveoli  containing  stainable  colloid.  (Fig.  52  and  53.)  The  similarity  in  the  primary 
and  the  detached  growth  on  the  tip  of  the  jaw  naturally  indicate  that  we  have  here  to 
deal  with  a  metastasis. 

There  is,  however,  a  further  possibility,  and  this  is  that  a  growth  has  developed 
from  an  implant  finding  lodgment  upon  the  prepared  site  of  an  injury.  We  have  fre- 
quently observed  that  fish  with  large  protruding  tumors  in  the  gill  region  attempt  to 
free  themselves  of  the  outgrowths  by  rubbing  the  tumor  upon  the  bottom  of  the  pond. 
This  is  evidenced  by  the  frequent  observation  of  tumors  which  have  been  worn  off  in  this 
way.  It  is  quite  easy  to  conceive  that  fragments  of  such  eroded  tumors  floating  in 
the  water  of  the  pond  might  find  lodgment  upon  the  injured  apex  of  the  lower  jaw.  If 
this  was  the  origin  of  this  outgrowth  on  the  tip  of  the  lower  jaw,  the  similarity  between 
the  primary  tumor  and  the  secondary  tumor  would  have  to  be  a  matter  of  coincidence. 
We  feel  we  may  safely  conclude  that  the  growths  on  the  tip  of  the  lower  jaw  are  true 
metastases  from  primary  growths  in  the  usual  locality,  the  lodgment  of  the  cells  by  way 
of  the  circulation  being  favored  by  reparative  processes  at  this  point,  or  that  the  growth 
is  a  result  of  implantation  through  the  medium  of  the  water.  From  the  standpoint 
of  determining  the  true  neoplastic  character  of  these  tumors,  the  evidence  would  be  in 
either  case  of  about  equal  value. 

A  case  of  still  greater  importance  has  to  do  with  a  2-year-old  brook  trout  from  the 
same  source,  in  which  a  tumor  measuring  7  by  8  by  14  millimeters,  of  pear  shape,  soft 
consistency,  and  dark  pinkish  color,  was  found  in  the  lowermost  portion  of  the  hind  gut 
or  rectum  just  within  the  anus.  (Fig.  25.)  Careful  examination  shows  that  the  tumor 
is  for  the  greater  part  covered  by  the  mucosa  of  the  intestine.  It  protrudes  within  the 
intestinal  canal,  which  is  greatly  flattened  and  pushed  to  one  side,  and  has  obviously 
been  obstructed  by  the  tumor.  (Fig.  54.)  A  section  made  from  the  wall  of  the  intes- 
tine, including  the  intestinal  lumen,  well  into  the  tumor,  presents  on  microscopic  exam- 
ination the  following  conditions : 


406  BULLETIN  OP  THE   BUREAU  OF  FISHERIES. 

The  tumor  is  of  alveolo-tubular  type,  the  greater  proportion  of  it  solid.  It  involves 
the  muscularis  mucosa  of  the  intestinal  wall,  bundles  of  muscles  derived  from  this  struc- 
ture running  through  its  substance.  In  the  more  open  portions  of  the  tumor,  alveoli 
containing  colloid  may  be  found.  Under  higher  power  (fig.  57)  the  epithelium  of  the 
tumor  both  in  the  alveolar  and  tubular  types  consists  of  large  cells  generally  of  high 
columnar  type.  The  protoplasm  is  deeply  stained;  the  nuclei  are  vesicular,  of  basilar 
location.  In  some  areas  marked  variation  in  size  and  character  of  the  epithelial  cells 
is  evident.  Karyokinetic  figures  are  not  infrequent.  The  heterotypic  nature  of  the 
epithelial  cells  is  best  seen  in  the  region  where  the  muscular  coat  of  the  intestinal  wall 
is  infiltrated.  (Fig.  57.) 

The  larger  proportion  of  the  tumor  is  rather  regular  in  formation,  homotypic  in 
character.  In  many  places  the  epithelium  is  so  closely  packed  that  scarcely  any  evidence 
of  alveolar  structure  may  be  made  out.  The  relation  of  the  intestinal  lumen  to  the 
tumor  growth  is  of  peculiar  importance.  Carefully  scanning  the  tumor  under  low  power 
a  point  may  be  found  where  the  intestinal  epithelium  spreads  out  into  a  single  layer 
upon  the  surface  of  the  tumor.  (Fig.  55.)  There  is  no  evidence  of  transition  from  the 
intestinal  epithelium  into  that  of  the  tumor;  in  fact  the  marked  columnar  character 
of  the  intestinal  epithelium,  with  its  frequent  goblet  cells,  is  clearly  distinguished  against 
the  background  of  tumor  tissue.  Upon  the  surface  of  the  tumor  the  single  layer  of 
epithelium  from  the  intestinal  papillae  extends  for  a  considerable  distance  upon  the  sur- 
face of  the  tumor,  the  uppermost  portion  of  which  is,  however,  eroded.  Evidences 
of  occasional  hemorrhages  upon  the  surface  may  be  found,  the  apex  of  the  tumor  being 
covered  with  a  distinct  clot.  In  other  portions  of  the  tumor  the  characteristic  appear- 
ance of  alveoli  of  irregular  shape  generally  filled  with  colloid  is  to  be  found  and  in  this 
region  the  tendency  to  papillary  growths  within  the  alveoli  is  quite  distinct.  (Fig. 
56.)  In  this  region  also  the  structure  of  the  muscularis  mucosa  is  apparent,  and  the 
marked  infiltrative  character  of  the  tumor  is  here  distinctly  evident. 

The  histologic  diagnosis  of  this  tumor  is  to  our  mind  quite  clear,  It  consists  of 
thyroid  tissue  presenting  the  characteristics  of  the  alveolo-tubular  type  of  tumor  of  the 
thyroid  in  the  Salmonidae.  It  furthermore  presents  in  certain  areas  that  tendency  to 
papillary  formation  which  is  so  frequent  in  these  tumors.  The  histological  picture 
and  the  presence  of  colloid  quite  clearly  determine  the  nature  of  this  growth.  It  is 
greatly  to  be  regretted  that  through  an  unforeseen  accident  the  thyroid  region  of  this 
fish  was  not  preserved.  We  have  no  evidence  as  to  the  nature  of  the  primary  growth 
in  the  thyroid  region.  Although  the  fish  presented  no  macroscopic  evidence  of  tumor, 
yet  there  is  little  doubt  that  a  primary  tumor  in  the  thyroid  region  existed.  The  fish 
was  taken  from  a  hatchery  in  which  one  of  the  most  outspoken  epidemics  of  the  disease 
we  have  yet  encountered  was  in  full  progress.  As  all  of  the  brook  trout  of  this  age 
succumbed  to  the  disease  in  the  course  of  two  seasons,  and  as  every  specimen  taken 
from  the  pond  in  which  this  fish  was  found  presented  macroscopic  or  microscopic  evidence 
of  the  disease,  there  is  little  reason  to  doubt  that  we  have  here  to  deal  with  a  metastasis 
from  a  tumor  originating  in  the  thyroid  tissue  of  this  fish. 


CARCINOMA   OP  THE  THYROID   IN   SAUfONOID   FISHES.  407 

We  have  expressed  our  reason  for  holding  that  the  growths  on  the  apex  of  the 
jaw  and  this  growth  in  the  wall  of  the  intestinal  tract  just  within  the  anus  are  instances 
of  genuine  metastasis  formation.  We  believe  that  a  wider  understanding  of  the  natural 
history  of  carcinoma  of  the  thyroid  of  the  Salmonidae  will  show  that  a  case  described 
by  Marine  and  Lenhart  (191  la,  p.  470)  is  more  probably  a  metastasis  than  a  tumor 
springing  from  misplaced  thyroid.  These  authors  describe  an  abdominal  goiter  in  a 
29-months-old  fish.  The  thyroid  mass  was  round,  circumscribed,  and  measured  one  by 
one-half  cubic  centimeter,  was  attached  to  the  cardiac  end  of  the  stomach  by  a  connective 
tissue  pedicle  and  extended  into  the  abdominal  cavity.  The  fish  had  a  large  ventral 
tumor  histologically  identical  with  the  abdominal  growth.  Because  an  examination 
of  the  visceral  regions  showed  no  such  deposits  of  thyroid  tissue,  these  authors  looked 
upon  this  specimen  as  an  enlarged  aberrant  thyroid  deposit.  They  also  report  having 
seen  growths  on  the  tip  of  the  lower  jaw  in  from  2  to  3  per  cent  of  all  fish  with  visible 
tumors  examined  by  them,  and  these  they  also  hold  to  have  sprung  from  misplaced 
thyroid  deposits. 

COMPARATIVE  PATHOLOGY. 

The  study  of  hyperplasia  and  carcinoma  of  the  thyroid  in  the  Salmonidae,  on  account 
of  the  great  similarity  in  the  changes  in  the  organ  of  the  fish  to  that  occurring  in  mam- 
mals, seems  likely  to  throw  important  light  upon  the  origin  of  certain  structures  which 
have  been  the  subject  of  extensive  study  in  the  thyroid  of  mammals.  Virchow  (1863), 
Wolfler  (1883),  Hitzig  (1894),  and  Michaud  (1906)  have  described  in  the  thyroid  of 
man  small  adenomata,  the  condition  being  known  as  struma  nodosa.  Virchow  held 
that  these  nodules  developed  by  proliferation  from  the  follicles  of  the  thyroid.  Wolfler 
held  that  they  developed  from  misplaced  embryonic  rests.  Hitzig  evidently  opposed 
the  theory  of  Wolfler  as  to  the  embryonic  origin  of  these  nodules  and  held  that  they 
developed  by  proliferation  from  the  normal  tissue  of  the  thyroid,  for  the  reason  that 
in  normal  thyroids  they  were  never  found.  Michaud  has  carefully  studied  the  genesis 
of  these  adenomata  and  agrees  with  Virchow  and  Hitzig  that  they  are  formed  by  pro- 
liferation from  normal  structures  of  the  thyroid. 

According  to  Michaud  these  growths  develop  by  changes  in  the  epithelium  of 
normal  follicles,  which  take  on  columnar  type  and  through  proliferation  of  the  cells  form 
extensions  and  protrusion  of  the  follicles  and  finally  by  budding  produce  new  follicles 
which  become  detached  from  the  original.  The  first  changes,  which  are  focal,  are 
restricted  by  the  surrounding  stroma,  which  takes  no  part  in  the  change.  From  this 
point  on  the  nodule  grows  by  proliferation  of  the  structures  within  it,  especially  those 
toward  the  center.  The  very  first  evidence  of  this  change  is  found  by  Michaud  in  the 
presence  in  the  thyroid  structure  of  long,  tortuous  clefts  or  tubes  with  cubical  or  colum- 
nar epithelium,  staining  more  deeply  than  the  surrounding  structures,  these  tubules 
having  already  been  noted  and  described  by  Hitzig.  From  these  tubules,  by  the  process 
of  budding  above  described,  are  developed  focal  nodules,  i.  e.,  struma  nodosa. 

It  will  be  seen  that  the  description  given  by  Hitzig  and  Michaud  for  the  development 
of  these  isolated  adenomata  in  the  mammalian  thyroid  is  exactly  like  the  beginning 


408  BULLETIN  OF  THE   BUREAU  OF  FISHERIES. 

changes  leading  to  carcinoma  of  the  thyroid  in  the  Salmonidae  as  we  have  described  it. 
Tn  figure  84  the  change  from  flattened  to  columnar  type,  with  deeply  staining  protoplasm, 
lengthening  and  flattening  of  the  tubules,  closely  resemble  those  found  in  the  mam- 
malian thyroid  by  Hitzig  and  Michaud,  and,  with  the  exception  of  the  hyperaemia, 
which  is  associated  with  the  more  intensive  chnges,  in  the  hyperplasia  of  the  thyroid  in 
the  Salmonidae.  The  advent  of  isolated  nodular  growths,  sometimes  sharply  circum- 
scribed (fig.  45),  indicates  that  focal  proliferation  of  the  thyroid  tissue  in  the  fish  fre- 
quently leads  to  the  development  of  nodules  presenting  the  picture  of  nodular  struma 
in  mammals.  The  structure  of  the  normal  thyroid  in  the  Salmonidse  is  so  simple  and  its 
amount  so  limited,  that  a  careful  study  of  this  structure  in  all  age  periods  of  the  fish 
renders  it  clear  that  the  advent  of  tubular  structures  with  columnar  epithelium  clearly 
represents  a  pathological  change,  and  here  we  are  not  troubled  with  the  many  questions 
which  arise  to  complicate  the  study  of  these  structures  in  the  mammalian  thyroid.  We 
can,  in  the  thyroid  of  the  Salmonidae,  definitely  exclude  the  idea  voiced  by  Kramer,  1910, 
that  such  tubules  in  the  mammalian  thyroid  were  probably  originally  the  remnants 
of  execretory  ducts  persisting  from  an  earlier  period  of  development  of  the  mammalian 
thyroid.  It  is  plainly  evident  from  the  study  of  the  normal  thyroid  in  the  Salmonidae 
and  the  genesis  of  hyperplasia,  nodular  growths  and  fully  developed  carcinoma,  that  the 
changes  in  this  organ  are  brought  about  by  the  action  of  some  agent  working  focally 
upon  the  epithelium  of  normal  vesicles,  and  we  can  clearly  exclude  all  possibility  of 
embryonic  rests  playing  a  part  in  the  genesis  of  circumscribed  adenomata  or  cancer. 

The  evidence  adduced  on  this  subject  therefore  confirms,  so  far  as  the  evidence  is 
applicable,  the  conclusions  of  Virchow,  Hitzig,  and  Michaud  that  struma  nodosa  develops 
as  the  result  of  focal  change  in  the  epithelium  of  normal  structures  of  the  thyroid.  The 
production  of  tubules  and  irregularly  distorted  spaces  lined  with  columnar  epithelium 
and  the  process  of  development  of  new  follicles  by  budding,  as  described  and  illustrated 
by  Michaud,  are  repeatedly  encountered  in  our  specimens,  especially  in  the  earliest  stages. 
(Fig.  36.)  The  theory  that  carcinoma  of  the  thyroid  develops  especially  from  the 
adenomata  of  nodular  struma  and  that  endemic  goiter  is  the  result  of  a  physiological 
hyperplasia  of  normal  thyroid  tissue,  finds  no  support  in  our  study  of  carcinoma  of  the 
thyroid  in  the  Salmonidae.  The  theory  of  Marine  that  iodine  affects  alone  physiological 
hyperplastic  changes  of  the  thyroid  tissue  and  does  not  affect  these  adenomata,  and  may 
thus  be  used  as  a  means  of  distinguishing  between  physiological  hyperplasia  and  cancer, 
is  obviously  untenable,  as  we  find  that  iodine,  as  well  as  mercury  and  arsenic,  affect 
not  only  fully  developed  carcinoma  of  the  thyroid  but  where  tumors  contain  individual 
adenomata  these  are  likewise  affected.  Well-developed  tumors  in  the  Salmonidse  some- 
times closely  simulate  the  structures  of  nodular  struma  in  the  mammal.  Figure  65 
represents  such  a  tumor  and  may  be  compared  with  figure  66,  struma  nodosa  in  man. 
The  tumors  of  the  fish  frequently  contain  the  so-called  Wachstum  centra  of  Aschoff . 
(Fig.  66.) 

Although  it  may  not  be  wise  to  go  too  far  in  the  comparison  of  carcinoma  in  the 
Salmonidae  with  carcinoma  of  the  thyroid  in  mammals,  yet  inasmuch  as  we  will  show 


CARCINOMA   OP  TH6  THYROID  IN   SAI^MONOID   PISHES.  409 

later  that  at  least  the  first  stages  of  this  disease  can  be  induced  in  mammals  through  the 
drinking  water,  such  a  comparison  at  the  present  time  becomes  even  more  profitable 
than  formerly.  The  final  relation  of  these  tumors  to  tumors  in  mammals  can  now  be  left 
to  experimental  investigation;  especially  the  production  in  mammals  of  metastasizing 
tumors  would  serve  to  clear  up  the  possible  relation  between  carcinoma  of  the  thyroid 
in  the  Salmonidae  and  carcinoma  of  the  thyroid  in  mammals.  For  the  present  we  con- 
sider that  we  have  more  firmly  established  the  fact  already  assumed  by  Plehn,  Pick, 
and  many  other  investigators,  that  we  are  here  dealing  with  carcinoma  of  the  thyroid 
in  fish. 

Pick,  in  his  excellent  article,  after  having  established  the  homotypic  and  hetero- 
typic  character  of  these  tumors,  compared  them  with  the  malignant  epithelial  tumors  of 
other  animals,  especially  carcinoma  of  the  breast  in  mice.  This  analogy  of  Pick's  is  well 
taken  and  we  feel  that  the  progress  of  experimental  cancer  research  has  since  demonstra- 
ted many  other  points  of  analogy,  which  we  shall  deal  with  later.  Pick  also  pointed  out 
that  certain  degenerative  and  regressive  changes  are  common  both  to  carcinoma  of  the 
thyroid  in  fish  and  the  epitheliomata  of  mammals.  The  impossibility  of  classifying 
the  different  types  of  carcinoma  of  the  thyroid  in  fish  affords  another  point  of  similarity 
with  carcinoma  of  the  breast  in  mice,  where  the  greatest  variety  of  histological  appear- 
ance may  be  found  in  the  same  tumor.  A  still  closer  analogy,  according  to  Pick,  is  to 
be  found  in  the  histological  character  of  the  growths  of  the  thyroid  in  fish  when  compared 
with  similar  tumors  in  man,  although  from  the  material  at  Pick's  disposal  he  had  no 
evidence  of  metastasis  formation,  such  as  we  are  now  able  to  bring. 

One  of  the  most  important  contributions  to  our  knowledge  of  the  various  types  of 
epithelial  proliferation  of  the  thyroid  structure  in  man  is  found  in  a  monograph,  based 
on  very  extensive  material,  entitled  "On  the  Epithelial  Forms  of  Malignant  Struma, " 
by  Langhans  (1907),  in  which  this  author  classifies  the  various  types  of  malignant 
growths  of  the  thyroid  in  man  under  the  following  heads : 

1.  Proliferating  struma. 

2.  Carcinomatous  struma,  the  usual  irregular  structure  of  carcinoma. 

3.  Metastasizing  struma. 

4.  Para  struma. 

5.  Small  alveolar,  large-celled  struma. 

6.  Malignant  papilloma. 

7.  Squamous  epithelioma. 

From  a  comparison  of  our  material  with  that  of  Langhans  we  find  that  in  the  fish 
tumors,  areas  of  proliferation,  or  in  some  instances  the  greater  part  of  the  structure 
of  a  tumor,  may  be  said  to  conform  to  one  of  three  of  the  six  types  described  by  Lang- 
hans for  man,  namely,  proliferating  struma,  carcinomatous  struma,  and  malignant 
papilloma.  Figure  59  illustrates  a  tumor  in  which  the  preponderating  type  is  almost 
identical  in  appearance  with  the  type  described  by  Langhans  for  proliferating  struma  and 
may  be  compared  with  figure  60,  made  at  the  same  magnification  from  one  of  Prof. 

8207  ° — 14 4 


410  BULLETIN   OF  THE  BUREAU  OF  FISHERIES. 

Langhans's  original  sections  which  he  was  kind  enough  to  transmit  to  us.  Carcinoma- 
tous  struma  in  man  has  its  analogy  in  many  of  the  illustrations  of  fish  tumors  given. 
Figure  63  illustrates  the  papillary  type  of  carcinoma  in  the  Salmonidae,  which  may 
be  compared  with  figure  27,  plate  6,  of  Langhans's  article,  illustrating  the  type  known 
as  struma  of  Geisslar.  Langhans's  group  6,  malignant  papilloma,  finds  its  counter- 
part in  many  of  the  fish  carcinomata,  papillomatous  areas  occurring  in  almost  all  tumors. 
Figure  61  illustrates  a  tumor  of  almost  pure  papillomatous  type  and  may  be  compared 
with  figure  62  from  one  of  Prof.  Langhans's  sections  of  malignant  papilloma  in  man  and 
illustrated  by  him  as  figure  32,  plate  7,  of  his  monograph. 

Pick  was  of  the  opinion  from  his  material  that  carcinoma  of  the  thyroid  in  the 
Salmonidae  was  a  condition  superimposed  upon  endemic  goiter  and  referred  to  the 
occasional  observation  of  malignant  growths  in  man  upon  the  basis  of  preexisting 
nonmalignant  struma.  He  suggested  that  endemic  goiter  might  be  distinct  from,  but 
was  the  predisposing  factor  in,  carcinoma  of  the  thyroid  in  fish. 

There  is  no  point  at  which  it  is  possible  for  us  to  draw  a  line  between  what  might 
be  called  endemic  goiter  in  the  salmonoid  fishes  and  carcinoma  of  the  thyroid.  Which- 
ever interpretation  one  may  desire  to  put  upon  this  process,  endemic  goiter  and  carci- 
noma of  the  thyroid  in  the  Salmonidae  are  one  and  the  same  thing.  Viewed  in  the  light 
of  modern  cancer  research,  it  appears  to  us  that  the  term  carcinoma  is  in  every  respect 
the  more  suitable.  The  first  positive  results  obtained  by  us  in  dogs  and  rats  must,  for 
the  present,  be  classed  as  diffused  parenchymatous  struma;  but  as  Bircher  has  already 
produced  nodular  struma  in  his  rats,  and  it  is  well  known  that  such  adenomata  of  the 
thyroid  develop  into  what  is  called  cancer  of  the  thyroid,  it  appears  to  us  quite  possible 
that  further  experiments  may  show  that  in  mammals  experimental  parenchymatous 
and  nodular  struma  are  but  the  early  stages  of  the  process  which  is  called  cancer  of  the 
thyroid.0 

o  At  the  meeting  of  the  Freiburger  medizinische  Gesellschaft  June  3,  1912,  Prof.  Aschoff  demonstrated  certain  preparations 
of  fish  and  dog  thyroids  which  had  been  transmitted  to  him  by  us.  The  report  of  this  meeting  in  the  Deutsche  Medizinische 
Wochenschrift,  no.  25,  June  20,  1912,  contains  certain  inaccuracies.  Prof.  Aschoff  is  reported  as  stating  that  Marine  and  Lenhart 
were  the  first  to  produce  struma  in  fish  experimentally,  and  spoke  of  our  work  as  a  repetition  of  such  experiments.  In  none  of 
the  publications  of  Marine  and  Lenhart  is  such  a.  claim  made.  We  do  not  know  of  any  investigators  having  had  the  facilities  or 
opportunity  to  carry  out  experiments  of  the  kind  detailed  in  this  report,  requiring,  as  they  do,  wild  fish  taken  from  regions  free 
from  the  disease  and  introducing  them  into  a  hatchery  under  conditions  with  proper  controls  to  demonstrate  that  they  have 
acquired  the  disease.  As  this  incorrect  report  has  been  quoted  by  Schittenhelm  and  Weichardt  in  their  monograph  on  endemic 
goiter  in  Bavaria,  it  seems  desirable  to  make  this  statement. 

In  their  quotation  of  Prof.  Aschoff's  remarks  these  authors  state  that  Aschoff  emphasized  the  similarity  of  our  tumors 
in  fish  with  the  pathological  findings  in  Basedow's  disease  in  man,  and  that  he  could  not  support  our  view  that  the  fish 
struma  was  carcinoma.  From  the  protocol  of  the  meeting  quoted  it  does  not  appear  that  he  expressed  himself  so  positively  as 
this.  He  demonstrated  the  similarity  of  the  preparations  with  Basedow's  disease  in  man,  but  this  must  have  applied  to  the 
sections  of  the  thyroid  enlargement  in  dogs,  and  not  the  fish  tumors.  This  report  quoted  the  fact  that  iodine,  as  shown  by 
Marine  and  I^enhart  and  confirmed  by  us,  when  added  to  the  water,  influenced  the  fish  tumors,  this  fact  appearing  to  be 
opposed  to  our  interpretation  that  the  fish  tumors  were  cancer,  and  it  did  not  emphasize  the  fact  that  sublimate  and  arsenic 
produced  the  same  result,  as  opposed  to  this  interpretation. 

In  this  connection  we  would  state  that  in  March,  1913,  Prof.  Aschoff  spent  a  day  at  our  institute  in  Buffalo,  and  after 
carefully  studying  all  of  the  preparations  upon  which  this  monograph  is  based,  including  the  specimens  of  metastases,  stated 
that  he  now  holds,  in  accord  with  us,  that  the  tumors  of  the  thyroid  in  the  Salmonidae  are  carcinoma. 


CARCINOMA   OF  THE  THYROID   IN   SALMONOID   FISHES.  4!  I 

OCCURRENCE  OF  THE  DISEASE  UNDER  WILD  CONDITIONS. 

It  is  through  the  domestication  of  trout  that  attention  was  first  attracted  to  thyroid 
disease  in  fish,  and  it  is  from  this  source  that  nearly  all  material  and  data  have  been 
derived,  both  in  this  country  and  in  Europe.  Nevertheless,  the  same  thyroid  process 
has  been  identified  with  certainty  among  adult  fish  living  in  open  natural  waters. 

The  most  important  example  of  the  kind  at  hand  is  a  whitefish  from  Lake  Keuka, 
N.  Y.  This  fish,  of  which  the  head  alone  came  to  our  hands,  is  a  member  of  the  genus 
Coregonus  of  the  Salmonidae  and  belongs  probably  to  the  common  species  of  whitefish 
of  Lake  Keuka,  Coregonus  clupeiformis .  (Fig.  67.)  It  was  reported  as  about  60 
centimeters  in  length,  probably  a  female,  though  the  sex  was  not  definitely  determined, 
was  caught  December  3,  1909,  in  water  about  15  meters  deep,  and  was  preserved  in 
formalin  about  two  days  later.  The  tumor,  which  is  described  in  detail  below,  is  of  good 
size  and  shows  the  typical  structure  common  to  this  growth  in  the  other  salmonoid 
species  considered. 

From  the  museum  of  the  University  of  Buffalo  has  come  to  us  a  brook  trout  (S. 
fontinalis}  having  a  large  thyroid  tumor.  (Fig.  69.)  The  fish  (diagram  23,  p.  30)  is  a 
female  17  centimeters  in  length  and  was  caught  by  Prof.  Herbert  M.  Hill  in  1902  from 
Hosmers  Creek,  near  Sardinia,  Erie  County,  N.  Y.  About  3  miles  of  this  stream  con- 
stituted a  fishing  preserve  of  the  nature  of  a  wild  stream.  It  had  for  several  years 
prior  to  this  time  been  stocked  with  5,000  to  10,000  fingerling  trout,  all  obtained  from 
the  New  York  State  Hatchery  at  Caledonia,  N.  Y.  Some  fry  of  the  same  species  were 
also  obtained  from  the  same  source  and  were  kept  in  a  pond  adjacent  to  the  creek 
where  they  were  reared  to  fingerling  size  and  then  liberated  in  the  creek.  No  artificial 
feeding  of  any  kind  was  done  in  the  stream  and  the  fish  in  question  was  either  planted  as  a 
fingerling,  or  possibly  as  fry  from  the  Caledonia  hatchery,  or  was  possibly  a  descendent 
of  some  few  wild  fish  which  occupied  the  stream  before  systematic  stocking  was  com- 
menced. It  is  more  probable  that  the  fish  was  originally  a  fingerling  sent  from  Cale- 
donia. From  its  size  it  was  probably  not  under  2  years  of  age. 

The  tumor  occurring  in  the  wild  living  whitefish  is  found  on  inspection  to  pro- 
trude in  both  gill  spaces  and  between  the  first  and  second  gill  arches  in  the  floor  of 
the  mouth.  It  infiltrates  the  structures  below  the  floor  of  the  mouth  beneath  the 
first  and  second  branchial  arches.  (See  diagram  16,  p.  28,  and  fig.  67.)  Under  the 
microscope  the  tumor  presents  areas  of  vesicular  type.  The  alveoli  are  small,  but 
few  of  them  contain  stainable  colloid.  The  bulk  of  the  tumor  is  made  up  of  areas  of 
closely  packed  deeply  staining  islands  of  cells,  presenting  the  merest  suggestion  of  alveolar 
structure.  The  cells  are  closely  packed,  the  nuclei  vesicular,  the  protoplasm  deeply 
staining.  Throughout  the  tumor  there  are  evidences  of  karyorrhexis.  The  tissue 
presents  the  appearance  of  not  having  been  freshly  preserved,  but  the  histological 
characteristics  are  sufficiently  discernible.  The  nuclei  are  vesicular,  and  nucleoli 
and  karyokinetic  figures  are  quite  frequent.  In  some  areas  the  cells  are  so  closely 
packed  as  to  present  the  appearance  of  spindle-celled  tissue.  The  whole  presents  the 
characteristic  picture  of  small  alveolar  carcinoma.  The  infiltrative  characteristics 


412  BULLETIN   OF  THE  BUREAU   OF  FISHERIES. 

are  best  observed  in  the  wall  of  the  large  vein,  where  we  find  the  cells  in  small  groups 
slightly  suggesting  an  alveolar  structure  where  they  have  penetrated  into  the  media 
of  the  venous  wall.  Shrinkage  owing  to  fixation  accentuates  the  chopped  out 
appearance  of  the  media.  (Fig.  68.)  In  studying  the  various  sections  in  which  this 
vein  is  included  one  finds  a  point  at  which  the  venous  wall  is  greatly  thinned,  and  at 
this  point  extensive  hemorrhage  into  the  surrounding  tumor  structure  has  occurred. 
In  the  same  section  groups  of  tumor  cells  are  to  be  found  in  the  venous  lumen.  (Fig. 
69.)  We  have  here  penetration  of  vessel  walls  by  the  tumor  cells.  Unfortunately, 
owing  to  the  fact  that  we  had  only  the  head  of  this  specimen  to  study,  we  do  not  know 
whether  the  viscera  contained  metastases  or  not. 

In  the  brook  trout  from  Hosmers  Creek,  N.  Y.  (diagram  23,  p.  30),  the  tumor  pre- 
sents itself  in  the  gill  spaces  on  both  sides  of  the  isthmus,  on  one  side  shaping  itself  into 
a  mass  the  size  of  a  hazelnut.  Protrusion  in  the  floor  of  the  mouth  is  visible  between 
the  first  and  second  gill  arches  on  the  side  of  the  large  tumor  and  in  the  median  section 
it  infiltrates  the  region  below  the  first  and  second  gill  arches.  The  fish  is  preserved 
in  alcohol.  Fixation  is  moderately  good.  The  section  of  the  tumor  measures  1 1  by 
9  mm.  On  macroscopic  inspection  of  the  section  a  deeply  staining,  sharply  defined 
nodule  measuring  6  by  8  mm.  is  clearly  discernible  embedded  in  a  more  lightly  staining 
tumor  mass.  Inspection  under  low  power  shows  that  there  is  a  distinct  difference  in 
the  appearance  of  the  surrounding  tumor  and  the  nodule,  the  nodule  being  separated 
from  the  tumor  by  a  well-defined  compression  capsule.  (Fig.  70.)  The  outlying 
portions  of  the  tumor  are  for  the  greater  part  composed  of  small  alveoli,  somewhat 
loosely  arranged,  with  occasional  larger  alveoli  of  irregular  shape  and  marked  columnar 
epithelium.  Wide  venous  channels  are  frequent  in  this  portion  of  the  tumor.  Within 
the  capsule  of  the  above-described  nodule  one  finds  the  whole  made  up  of  somewhat 
loosely  arranged  islands,  strands,  and  masses  of  cells.  The  central  portion  of  the 
nodule  presents  wide  venous  sinuses  without  delimiting  intima  and  areas,  which  are 
no  doubt  the  result  of  hemorrhage.  Under  high  power  one  finds  the  cells  in  certain 
portions  of  the  nodule  to  be  so  arranged  as  to  suggest  small  alveoli,  but  for  the  greater 
part,  especially  in  the  well-preserved  marginal  portions  of  the  nodule,  the  cells  present 
a  distinct  spindle  character,  and  great  variability  in  size  of  the  nuclei,  which  are  vesicular 
with  one  or  two  nucleoli.  The  protoplasm  of  the  cells  stains  deeply,  is  rather  sparse, 
and  karyokinetic  figures  are  very  numerous.  Certain  areas  may  be  found  in  which 
the  spindle  character  of  the  cells  is  so  pronounced  as  to  suggest  the  diagnosis  of  spindle- 
celled  sarcoma.  (Fig.  71.)  Gradual  transitions  of  such  areas  into  an  arrangement  of 
cells  clearly  showing  their  derivation  from  the  poorly  formed  alveoli  indicate  their 
character.  We  have  here  a  nodule  of  malignant  tumor  growth  in  a  mass  of  tumor 
tissue  of  less  malignant  appearance,  carcinoma  solidum  simulating  spindle-celled 
sarcoma. 

In  June,  1913,  a  large  landlocked  salmon  (S.  sebago)  with  a  large  thyroid  tumor 
was  caught  in  Sebago  Lake,  Me.,  by  Dr.  Charles  F.  Parker,  of  North  Windham,  Me. 
Dr.  Parker  recognized  the  nature  of  the  growth  and  forwarded  it  to  us  through  Dr.  W.  C. 
Kendall,  of  the  Bureau  of  Fisheries.  The  fish  was  about  4  years  of  age,  measured  23 


CARCINOMA   OF  THE  THYROID  IN   SA^MONOID   FISHES.  413 

inches  in  length  and  in  its  rather  emaciated  condition  weighed  4  pounds.  A  salmon  of 
this  length  in  health  should  weigh  6  to  8  pounds.  A  large  thyroid  tumor  involved  the 
whole  gill  region,  vegetating  in  the  floor  of  the  mouth  and  presenting  on  the  ventral 
surface  several  cystic  lobes  which  kept  the  gills  and  gill  covers  well  distended.  (Fig.  72,) 

Sebago  Lake  is  located  in  the  southwestern  part  of  Maine.  It  has  an  area  of  about 
45  square  miles  and  a  general  depth  of  316  feet.  It  has  but  few  shoal  places,  the  depth 
of  water  often  reaching  close  to  the  shores,  which  are  for  the  most  part  rocky,  save  in 
a  few  shallow  coves.  The  lake  has  little  aquatic  vegetation;  the  water  is  regarded 
as  unquestionably  pure  and  is  the  source  of  supply  for  the  city  of  Portland.  While  the 
fish  had  been  living  in  a  wild  state  for  two  or  three  years,  it  was  originally  planted  from 
a  fish  hatchery,  where  it  may  have  contracted  the  disease.  Microscopic  inspection 
of  this  tumor  (see  fig.  75)  shows  it  to  be  almost  entirely  of  the  alveolar  type,  showing 
at  the  center  areas  of  cystic  colloid  degeneration. 

These  four  tumor-bearing  fish  were  living  under  wild  natural  conditions  when 
taken.  All  can  be  related  more  or  less  remotely  to  fish  culture.  They  were  taken  from 
waters  in  inhabited  regions,  in  which  fish  culture  has  been  practiced  for  years,  and  these 
waters  had  frequently  received  the  products  of  hatcheries.  The  trout  inhabited  a  stocked 
stream,  and  was  possibly  the  product  of  a  hatchery  and  fed  artificially,  or  was  descended 
from  fish  so  treated.  The  landlocked  salmon  was  probably  planted  from  a  hatchery.  No 
whitefish  are  fed  artificially  nor  reared  to  maturity  in  domestication.  The  product  of 
their  artificial  propagation  is  planted  soon  after  hatching.  The  most  that  may  be  said, 
therefore,  as  far  as  the  relation  of  this  tumor-bearing  whitefish  to  domestication  is  con- 
cerned, is  that  it  may  have  been  artificially  hatched,  planted  before  feeding,  and  was 
living  in  a  large  lake  which  received  the  drainage  from  a  large  trout  hatchery  and  breed- 
ing establishment  at  which  the  thyroid  disease  was  endemic  and  epidemic.  It  was  taken 
within  5  miles  of  the  point  of  entry  of  this  drainage  inflow. 

In  one  of  the  small  lakes  of  the  Adirondack  Mountains  of  New  York,  which  have 
been  stocked  with  trout  from  hatcheries,  anglers  occasionally  report  the  taking  of  fish 
with  visible  tumors  at  the  throat. 

In  Europe  Hofer  (1904,  p.  194)  reports  the  disease  in  wild  lake  trout  (Trutta  lacus- 
tris)  living  in  the  Mondsee.  Dr.  Plehn  informs  us  that  occasionally  trout  with  thyroid 
tumors  and  living  under  wild  conditions  in  the  streams  of  Bavaria  are  sent  to  the 
Bavarian  Fisheries  Biological  Station  for  examination. 

OCCURRENCE  AND  COURSE  OF  THE  DISEASE  UNDER  DOMESTICATION 

DISTRIBUTION  OF  THE  DISEASE  IN  UNITED  STATES  HATCHERIES. 

The  thyroid  tumor  among  fishes  is  undoubtedly  of  wide  distribution.  We  believe 
it  occurs  almost  universally  where  trout  are  made  the  subject  of  artificial  propagation 
and  rearing  under  the  ordinary  conditions  of  fish  culture  in  the  United  States.  A 
complete  canvass  of  all  the  trout-breeding  establishments  in  the  country  has  not  yet 
been  made,  but  such  an  investigation  would  beyond  question  indicate  the  distribution 
of  the  disease  as  coextensive  with  trout  culture.  The  following  list  gives  the  places 


BULLETIN   OF  THE   BUREAU   OF   FISHERIES. 


at  which,  from  an  adequate  examination  of  material,  the  disease  is  definitely  known 
to  exist  or  to  have  existed  in  an  advanced  stage  as  expressed  by  the  exhibition  of  visible 
tumors. 


District  of  Columbia. 
Iowa:  Manchester. 
Maine:  Craig  Brook,  Auburn. 
Michigan:  Paris;  North ville. 
Missouri:  Neosho. 
Montana:  Bozeman. 
New  Hampshire:  Nashua. 
New     York:    Bath;    Margaretville 
hatcheries. 


and      other 


Pennsylvania:  Spruce  Creek;  Glen  Eyre. 

South  Dakota:  Spearfish. 

Virginia:  Wythe ville. 

Vermont:  Roxbury;  St.  Johnsbury. 

Washington:  North  Yakima. 

West  Virginia:  White  Sulphur  Springs. 


NAMES  OF  SPECIES  AND  HYBRIDS. 

While  the  disease  primarily  and  chiefly  is  found  in  the  brook  trout,  it  has  been 
observed  among  all  the  following  species  and  hybrids  in  the  United  States.  Two  of 
these,  the  brown  trout  and  Loch  Leven  trout,  are  introduced  species,  and  one — the 
whitefish — belonging  to  a  subfamily  of  the  Salmonidae,  is  not  the  subject  of  fish  culture 
as  an  adult  and  is  represented  by  only  one  specimen  bearing  a  tumor,  this  being  a  wild 
fish  from  a  lake.  It  is  quite  certain  that  this  list  will  be  much  extended  as  fast  as  other 
species  of  salmonoids  are  brought  under  domestication.  The  single  species  which, 
though  bred  artificially,  can  not  yet  be  included  among  the  species  subject  to  thyroid 
carcinoma,  is  the  sea  trout  (Salmo  trutta  Linnaeus),  introduced  into  the  United  States 
as  the  Scotch  sea  trout. 

American    brook    trout;  square-tail    trout;  redspot    trout; 

speckled  trout Salvelinus  fontinalis  (Mitchill). 

Rainbow  trout Salmo  irideus  Gibbons. 

Landlocked  salmon;  Sebago  salmon;  Schoodic  salmon Salmo  sebago  Girard. 

Loch  Leven  trout Salmo  levensis  Walker. 

Brown  trout;  von  Behr  trout Salmo  fario  Linnaeus. 

Atlantic  salmon Salmo  salar  Linnaeus. 

Great  Lakes  trout;  lake  trout;  MackinaAv  trout;  namaycush 

trout;  longe;  lunge;  togue;  laker Cristivomer  namaycush  (Walbaum). 

Humpback  salmon. Oncorhynchus  gorbuscha  (Walbaum). 

Common  whitefish Coregonus  clupeiformis  (Mitchill). 

Hybrid  salmon: 

Female  silver  salmon \ 

Male  humpback  salmon . . .  J 

Female  silver  salmon 1 

Male  chinook  salmon f 

Female  blueback  salmon.  .1 

Male  humpback  salmon . .  .  J 

Female  humpback  salmon  .1 

Male  blueback  salmon J 

Female  brook  trout 1 

Male  landlocked  salmon . . .  J 
Hybrid  trout: 

American  brook  trout ] 

American  saibling  or  sunapee  trout .  J  " 


jOncorhynchus  kisutch  (Walbaum). 
'  \Oncorhynchus  gorbuscha  (Walbaum). 
[Oncorhynchus  kisutch  (Walbaum). 
'\Oncorhynchus  tschawytscha  (Walbaum). 
jOncorhynchus  nerka  (Walbaum). 
\Oncorhynchus  gorbuscha  (Walbaum). 
JOncorhynchus  gorbuscha  (Walbaum). 
[Oncorhynchus  nerka  (Walbaum). 
fSalvelinus  fontinalis. 
\Salmo  sebago. 

fSalvelinus  fontinalis. 
'  [Salvelinus  aureolus  (Bean). 


CARCINOMA   OF  THE   THYROID   IN   SALMONOID   FISHES.  415 

Besides  the  American  brook  trout  and  the  rainbow  trout  introduced  into  Europe, 
the  following  European  species,  at  least,  have  been  observed  as  the  subject  of  thyroid 
carcinoma  in  Europe : 

Atlantic  salmon Salmo  salar  Linnaeus. 

Forelle;  Bachforelle;  brown  trout,  yellow  trout,  brook  trout, 

river  trout,  etc Salmo  fario  Linnaeus. 

Loch  Leven  trout Salmo  levensis  Walker. 

Seeforelle  or  lake  trout Salmo  lacustris  Linnanis. 

Ombre  chevalier,  European  charr  or  saibling Salvelinus  salvelinus  (Linnaeus).     [Salve- 

linus  alpinus  (Linnaeus)  of  most  authors.] 

GEOLOGICAL  FORMATION  AT  FISH  HATCHERIES. 

That  the  distribution  of  goiter  possesses  a  definite  relation  to  the  geological  for- 
mation has  been  repeatedly  advanced  and  denied.  McClellan  in  1837  pointed  out  the 
predisposing  quality  of  the  mountainous  limestone  and  the  nagelfluhe.  The  principal 
exponent  of  this  theory  in  Europe  has  been  H.  Bircher  (1883).  According  to  this  author 
the  greatest  concentration  of  goiter  is  found  in  the  Molasse  highland.  The  Tertiary 
formation  also  predisposes  to  goiter,  whereas  the  Jurassic  formation  and  the  primary 
formation  of  the  Alps  are  free  from  the  disease.  Kocher  (1889),  who  with  the  assistance 
of  25  of  his  scholars  examined  76,606  school  children  between  the  ages  of  7  and  15 
years,  was  not  able  to  justify  these  conclusions  of  Bircher,  as  he  found  that  the  Jurassic 
formation  was  in  no  way  free  from  goiter,  neither  was  the  fresh-water  Molasse.  Recently 
Hesse  (1911)  in  a  study  of  the  distribution  of  goiter  in  the  Kingdom  of  Saxony,  was 
able  only  in  part  to  confirm  the  theory  of  Bircher,  as  he  found  next  to  the  highest  per- 
centage of  the  disease  in  the  Eibenstock  granite  and  the  highest  in  the  eruptive  Mus- 
covite gneiss,  both  of  which  are  formations  that  according  to  Bircher  should  be  free 
from  the  disease.  Schittenhelm  &  Weichardt,  in  the  study  of  goiter  in  Bavaria  (1912), 
found  that  one  of  the  most  extensive  distributions  of  goiter  in  that  country  was  in 
the  Bavarian  forest,  which  lies  upon  the  primary  granite  formation.  These  authors 
conclude  that  the  geological  formation  is  not  a  primary  determining  factor  in  the  endemic 
distribution  of  goiter,  but  that  the  infection  of  the  water  supply  is.  The  distribution 
of  goiter  in  the  mountainous  southern  portion  of  Bavaria,  as  well  as  in  Switzerland, 
they  consider  to  be  due  to  certain  conditions  depending  upon  the  mountains  themselves 
and  not  their  geological  formation  as  such. 

McCarrison  in  his  analysis  of  conditions  in  the  goitrous  regions  of  Chitral  and  Gilgit 
in  Northern  India  finds  that  the  water  supply  of  the  Chitral  district  comes  from  meta- 
morphic  rocks  consisting  mainly  of  gneiss  and  slate  and  to  a  lesser  extent  of  limestone. 
There  are,  however,  certain  large  outcrops  of  limestone,  and  it  is  from  these  that  the 
most  goitrous  villages  derive  their  water  supplies.  Likewise  the  highly  goitrous  villages 
of  Gilgit  are  supplied  by  water  from  a  valley  which  contains  a  considerable  outcrop  of 
limestone.  These  results  are  likewise  at  variance  with  the  theory  of  Bircher  concerning 
the  influence  of  geological  formation. 

Dieterle  (1913)  after  a  personal  examination  of  a  series  of  goitrous  localities  in 
Switzerland  comes  to  the  conclusion  that  neither  the  geologic  formation  upon  which 


41 6  BULLETIN   OF  THE   BUREAU   OF   FISHERIES. 

goitrous  regions  are  located  or  the  geologic  formation  from  which  the  water  supply 
springs  is  the  determining  factor  in  the  incidence  of  goiter.  He  has  found  regions 
located  upon  and  supplied  with  water  from  pure  Jura  formation,  with  from  12  to  40 
per  cent  of  goiter,  and  comes  to  the  conclusion  that  the  boundaries  of  localities  in 
which  endemic  goiter  occurs  are  purely  geographic,  such  as  certain  valleys,  along  cer- 
tain rivers,  or  the  sides  of  certain  mountains. 

To  determine  whether  there  is  any  connection  between  the  geological  formation  at 
the  various  hatcheries  of  the  Government  where  trout  are  bred  and  the  endemic  conditions 
existing  in  most  of  them,  we  have  obtained  from  the  United  States  Geological  Survey  a 
statement  concerning  the  formation  at  most  of  the  centers  of  fish  culture  throughout 
the  country.  All  the  data  are  included  here,  whether  the  station  concerned  is  engaged 
with  trout  culture  or  not.  In  some  cases  only  general  information  is  available. 

No  correlation  between  geological  formation  and  the  occurrence  of  thyroid  disease 
is  at  present  even  suggested  from  the  data  at  hand,  which  is  here  shown  for  purposes  of 
record  in  view  of  its  possible  future  value.  Most  of  the  water  supplying  stations  subject 
to  thyroid  disease  arises  among  the  geological  formations  of  primary  order.  Only  one  is 
secondary  (Triassic)  and  only  a  few  tertiary  and  quaternary. 

ALASKA. 
Yes  Bay. — Crystalline  schists,  probably  Carboniferous. 

ARKANSAS. 

Mammoth  Springs. — Probably  in  Proctor  or  Potosi  limestone.     Cambrian  system. 

CALIFORNIA. 

Baird. — Baird  formation.     Carboniferous  system.     This  underlies  a  bluff  of  the  Carboniferous 
McCloud  limestone. 

Battle  Creek. — Tuscan  tuff  with  some  lava  beds.     Tertiary. 

Mill  Creek. — On  border  of  alluvium  of  Sacramento  Valley,  and  of  Tuscan  tuff  and  lava.     Tertiary  age. 

COLORADO. 

Leadville. — Crystalline  rock;  pre-Cambrian  age. 

GEORGIA. 

Bullochville. — Formation  not  known.     Probably  granite  and  gneiss.     Archean  gneiss. 

ILLINOIS. 

Quincy. — Burlington  and  Keokuk  limestones;  Carboniferous  age. 

Meredosia. — Glacial  sand  and  clay.  One  hundred  feet  more  or  less  below  the  surface  is  Carbonif- 
erous limestone.  Same  as  at  Quincy. 

IOWA. 

Manchester. — Devonian  limestone  with  chert  nodules. 

Fairport. — At  contact  of  Carboniferous  shales  on  Devonian  limestone. 


CARCINOMA   OF  THE  THYROID   IN   SALMONOID   FISHES.  417 

MAINE. 

Boothbay  Harbor. — Schists  and  gneisses  with  dikes  of  granite.     Age  unknown. 

Craig  Brook  (East  Orland). — Granite.     Silurian  or  Devonian  age. 

Grand  Lake. — Mica  schist.     Age  unknown.     Cut  by  granite  of  Silurian  or  Devonian  age. 

Green  Lake. — Granite.     Silurian  or  Devonian  age. 

Lake  Auburn. — Mica  schists.     Age  unknown.     Cut  by  granite  of  probable  Ordovician  age. 

Lake  Sebago. — Granite  and  granite  gneiss.     Probably  Silurian  or  Devonian  age. 

Portland. — Largely  quartzose  schist.     Age  unknown. 

York. — Volcanic  tuff  and  lava  flows  cut  by  some  granite.     Age  unknown. 

MARYLAND. 

Havre  de  Grace. — Potomac  formation.     Carboniferous  age. 
Bryan's  Point. — Talbot  formation.     Quaternary  system. 

MASSACHUSETTS. 

Woods  Hole. — Pleistocene  glacial  gravels. 

Gloucester. — Probably  Rockport  granite.     Carboniferous  age. 

East  Freetown. — Granite.     Probably  Paleozoic  age. 

Hartsville. — Stockbridge  limestone  next  to  Cheshire  quartzite.     Cambrian  age. 

Plymouth. — Pleistocene  glacial  gravels  and  sands. 

MICHIGAN. 

Northville. — Cold  Water  shale.     Carboniferous  age. 

Alpena. — Antrim  shale.     Devonian  age.     Has  a  little  gas. 

Charlevoix. — Antrim  shale.     Devonian  age. 

Detroit. — Antrim  shale  and  Traverse  limestone.     Devonian  age. 

Sault  Ste  Marie. — Lake  Superior  sandstone.     Cambrian  age. 

MINNESOTA. 

Lester  Park,  Duluth. — Lavas  of  Keeweenawan  series.     Algonquin  age. 

Homer. — Immediately  underlain  by  St.  Croix  sandstone,  bluffs  to  south  are  St.  Peter  sandstone, 
Shakopee  limestone,  Jordan  sandstone,  and  St.  Lawrence  limestone.  Copious  spring  waters  come  from 
these  sandstone  formations.  The  St.  Lawrence  is  of  Cambrian  age ;  the  other  of  Ordovician  age. 

MISSISSIPPI. 

Tupelo. — Pleistocene  sands  resting  upon  sandy  portion  of  Selma  chalk.     Cretaceous  age. 

MISSOURI. 
Neosho. — Boone  limestone.     Carboniferous  age. 

MONTANA. 

Bozeman. — Neocene  lake  beds.     Tertiary  age. 

NEW   HAMPSHIRE. 

Nashua. — Sand  beds  of  glacial  lake.     Quaternary  age. 

Lake  Sunapee. — (East  side)  Granite;  age  unknown.  Heavy  cover  of  glacial  gravel;  quaternary 
age.  (West  side.)  Formations  unknown. 


41 8  BULLETIN   OF  THE   BUREAU  OP  FISHERIES. 

NEW  YORK. 

Bath. — Chemung  formation.     Devonian  age. 

Buffalo. — Salina  formation,  Silurian  age,  and  Onondaga  limestone  and  Hamilton  shale,  Devonian 
age. 

Caledonia. — Onondaga  limestone  and  Oriskany  sandstone,  Devonian  age;  Salina  shale,  Silurian  age. 

Cape  Vincent. — Trenton  limestone.     Ordovician  age. 

Chautauqua  Lake. — Chemung  formation.     Devonian  age. 

Cold  Spring  Harbor. — Glacial  gravel  and  sand.     Quaternary  age. 

Constantia. — Medina  sandstone.     Silurian  age. 

Margaretville. — Catskill  formation.     Devonian  age. 

Old  Forge. — Mica  gneiss.     Archean  age. 

Saranac  Lake. — Granite,  gabbro,  gneiss,  and  schist.     Archean  age. 

NORTH  CAROLINA. 

Edenton. — Sand  and  clay.     Quaternary  age. 

OHIO. 

Put-in  Bay. — Lower  Helderberg  limestone.     Devonian  age. 

OREGON. 

Clackamas. — Volcanic  breccia;  probably  Tertiary  age. 

Cazadero. — Volcanic  breccia;  probably  Tertiary  age. 

Willamette  River. — Flood  plain  sand  and  clay,  Quaternary  age;  Sandstone,  Eocene  age. 

Rogue  River. — Formation  unknown. 

PENNSYLVANIA. 

Bellefonte. — Trenton  limestone.     Ordovician  age. 

Freeland. — Coal  measure  sandstone  and  shale.     Carboniferous  age. 

Weissport. — Hamilton  shale.     Devonian  age. 

Spruce  Creek. — Trenton  limestone.     Ordovician  age. 

SOUTH  DAKOTA. 

Spearfish. — Spearfish  formation.     Triassic  age. 

TENNESSEE. 
Erwin. — Honaker  limestone.     Cambrian  age. 

TEXAS. 

San  Marcos. — Del  Rio  formation.     Cretaceous  age. 

UTAH. 

Provo  Valley. — Mesozoic  rocks;  mainly  shales  of  Mesozoic  age. 

VERMONT. 

Groton. — West  part  of  town  in  granite.     Age  unknown.     East  part  in  mica  slate;  probably  Ordovic- 
ian age. 

Sharon. — Mica  schist;  probably  Ordovician  age. 

St.  Johnsbury. — Mica  schist;  probable  Ordovician  age,  with  much  glacial  gravel  of  Quaternary  age. 

Swanton. — Trenton  limestone.     Ordovician  age. 

VIRGINIA. 

Wytheville. — Shaly  limestone.     Cambrian  age. 


CARCINOMA   OF  THE   THYROID   IN   SALMONOID   FISHES.  419 

WASHINGTON. 

Baker  Lake. — Limestones  and  schists  to  the  south  and  volcanic  rocks  to  the  north  and  west.     Age 
unknown. 

Birdsview. — Schists  partly  ferruginous.     Age  unknown. 
Little  White  Salmon  River. — Basalt.     Late  Tertiary  age. 
Big  White  Salmon. — Basalt.     Late  Tertiary  age. 

WEST  VIRGINIA. 

White  Sulphur  Springs. — Romney  shale.     Devonian  ».ge. 

WISCONSIN. 

Bayfield. — Lake  Superior  sandstone,  Cambrian  age,  deeply  buried  under  glacial  lake  clay.    Quater 
nary  age. 

Madison. — Madison  sandstone,  Cambrian  age,  under  heavy  cover  of  glacial  gravel. 

CHEMISTRY  OF  THE  WATER  SUPPLIES. 

There  are  no  very  definite  chemical  standards  by  which  the  fish-cultural  value  of  a 
water  may  be  predetermined  without  the  test  of  experience  with  fishes.  The  ordinary 
sanitary  analysis  is  of  almost  no  value,  the  showing  with  respect  to  dissolved  air  gases, 
which  are  of  primary  importance  in  fish  culture,  being  usually  omitted.  As  for  a  mineral 
analysis,  it  is  difficult  to  interpret  it  in  fish-cultural  terms  since  fishes  thrive  in  waters 
of  such  varied  chemical  content  that  conclusions  can  not  be  drawn  from  a  statement  of 
the  inorganic  materials  dissolved,  unless  they  show  the  water  to  be  so  heavily  mineral- 
ized that  it  is  no  longer  fresh,  or  unless  it  contains  the  metals  known  to  be  highly  poison- 
ous to  fishes.  Even  in  the  latter  case  special  determinations  must  be  made  and  large 
quantities  of  water  used,  since  some  metals,  for  instance,  mercury  and  copper,  are  fatal 
to  salmonoids  in  dilutions  far  beyond  detection  in  ordinary  routine  mineral  analysis. 

In  order  to  lay  a  foundation  for  the  possible  establishment  of  fish-cultural  standards 
in  water  analysis,  by  long  fish-cultural  experience  with  waters  whose  chemical  consti- 
tution was  determined,  the  Bureau  of  Fisheries  has  had  analyses  made  of  many  waters 
used  to  supply  its  various  stations  for  the  propagation  of  fish  throughout  the  country. 
These  analyses  have  been  made  by  the  Bureau  of  Chemistry,  Department  of  Agriculture. 
Since  not  all  these  stations  engaged  in  trout  propagation  whose  water  supplies  have  been 
examined  chemically  have  been  thoroughly  investigated  to  determine  their  status  with 
respect  to  thyroid  disease,  it  is  not  possible  to  divide  them  into  those  which  are  subject 
to  and  those  which  are  free  from  the  disease,  if,  indeed,  there  are  any  belonging  unequivo- 
cally to  the  latter  class.  We  have  therefore  shown  only  the  results  (table  u)  for  waters 
supplying  such  stations  as  are  known  to  have  the  trout  thyroid  disease  endemic,  save 
the  last  two  (no.  11737  and  11738),  which  supply  the  State  hatchery  at  Cold  Spring 
Harbor,  N.  Y.,  and  one  of  which  appears  to  be  at  present  free  from  the  disease.  By  a 
scrutiny  of  the  mineral  content  of  this  water  at  the  latter  station,  nothing  distinctive 
is  to  be  found.  It  is  low  in  total  solids  and  therefore  very  lightly  mineralized;  the 
chlorids,  sulphates,  silicates,  and  bicarbonates  of  the  common  earth  metals  make  up  the 
bulk  of  the  residue.  These  statements  apply  equally  to  many  of  the  waters  in  which 


420  BULLETIN   OF  THE   BUREAU   OF   FISHERIES. 

the  disease  is  developed.  It  is  in  our  opinion  highly  improbable  that  any  of  the  factors 
in  causation  of  the  disease  are  to  be  found  among  the  variations  of  the  concentration 
in  which  the  common  earth  salts  and  other  matter  are  found  in  these  waters. 

None  of  the  analyses  shown  in  table  n  disclose  any  trace  of  iodine  or  bromine,  but 
only  ordinary  volumes,  as  a  single  liter,  were  devoted  to  the  reactions  for  these  elements. 
In  order  to  test  further  the  presence  of  these  elements  in  the  water  of  the  Craig  Brook 
station,  where  a  large  part  of  our  data  has  been  obtained,  we  have  had  two  samples  of 
15  liters  each  used  entirely  by  the  Bureau  of  Chemistry  for  determining  iodine  and  bro- 
mine in  two  sources  of  water  at  the  Craig  Brook  station.  The  Craig  Pond  water  (no. 
5867)  is  the  chief  water  supply  of  the  Craig  Brook  station.  It  is  slightly  augmented, 
before  reaching  the  fish  ponds,  by  small  volumes  of  spring  water  not  subjected  to  anal- 
ysis. The  farm-house  spring,  whose  complete  content  is  not  shown,  is  a  minor  supply 
arising  on  the  station  grounds,  and  is  probably  typical  of  the  springs  of  the  immediate 
neighborhood,  such  as  the  lawn  spring  (no.  5868)  whose  content  appears  in  table  n. 
The  Craig  Brook  water  itself  is  in  this  way  shown  to  contain  i  part  of  iodine  to 
1,310,000,000  parts  of  water;  and  i  part  of  bromine  to  149,000,000  parts  of  water.  The 
farm-house  spring  showed  about  the  same  quantities  of  each  element:  of  iodine,  i  part 
to  1,250,000,000;  of  bromine,  i  part  to  142,800,000.  The  ratio  of  iodine  to  bromine 
was  the  same  in  the  two  sources,  i  to  8.7.  As  the  delicacy  of  the  iodine  test  detects 
about  one  one-hundredth  milligram  of  iodine,  the  1 5-liter  sample  contained  a  little  more 
than  enough  for  the  reaction. 

Since  thyroid  hyperplasia  begins  in  the  Craig  Brook  water  and  is  reduced  by  iodine 
in  dilutions  which,  though  much  attenuated,  are  yet  much  richer  in  iodine  than  the 
above,  it  seems  certain  that  the  extreme  dilution  of  iodine  found  to  occur  naturally  in 
the  water  is  without  appreciable  physiological  effect.  Most  brook  water  will  probably 
be  found  to  contain  iodine  in  quantities  comparable  to  those  in  Craig  Brook. 

Dissolved  oxygen. — No  lack  of  dissolved  oxygen  contributes  to  the  thyroid  disease 
at  the  Craig  Brook  station.  Flowing  brooks  almost  invariably  contain  all  the  oxygen 
the  water  will  absorb  from  the  air.  The  Craig  Brook  water  was  several  times  titrated 
for  oxygen  and  was  found  to  be  air-saturated.  The  water  at  the  outlets  of  troughs  and 
cement  tanks  containing  trout  was  likewise  examined  and  the  amount  of  oxygen  removed 
by  the  fish  was  determined.  A  cement  tank  containing  about  40  wild  trout  diminished 
the  oxygen  content  by  0.13  cubic  centimeter  per  liter.  Sixty-eight  yearling  trout  held 
in  a  wooden  trough  removed  0.4  cubic  centimeter  of  oxygen  per  liter,  leaving  an  oxygen 
content  of  6.8  cubic  centimeters  per  liter  at  a  water  temperature  of  15°  C.,  which  is  barely 
short  of  air-saturation. 

Spring  waters  not  infrequently  emerge  from  the  earth  with  a  considerable  deficiency 
of  oxygen.  One  such  was  found  draining  into  Craig  Brook,  holding  only  2.39  cubic 
centimeters  per  liter  at  1 7.25° C.,  which  is  about  35  per  cent  of  air-saturation.  Its  volume 
was  insignificant,  and  no  additions  of  this  sort  to  the  stream  perceptibly  affect  its 
oxygenation. 

Lack  of  oxygenation  can  be  excluded  from  the  consideration  of  causation. 


CARCINOMA  OP  THE  THYROID  IN  SAI^MONOID  PISHES. 


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SANITARY  EXAMINAT 

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CARCINOMA   OF  THE   THYROID   IN   SAL,MONOID   FISHES. 


423 


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424 


BULLETIN  OF  THE   BUREAU   OF   FISHERIES. 


McCarrison,  in  his  observations  (1906)  on  endemic  goiter  in  India,  considers  the 
dissolved  content  of  the  waters  concerned  and  is  unable  to  find  anything  of  significance 
in  its  relation  to  the  amount  of  goiter.  For  the  villages  of  the  Chitral  Valley,  all  centers 
of  goiter,  he  gives  the  foregoing  table  (table  in).  The  meager  chemical  data  here 
shown  afford  no  clue  to  the  explanation  of  the  distribution  of  goiter  in  the  villages. 

He  gives  similar  data  for  the  single  water  supply  of  the  several  component  villages 
known  collectively  as  Gilgit,  which  are  located  in  a  series  along  the  water  channel  from 
above  downward,  so  that  an  increasing  pollution  occurs  toward  the  lowermost  village. 
There  is  here  an  increase  of  the  incidence  of  goiter  from  above  downward,  culminating 
at  the  lowermost  village.  In  the  following  analysis  of  the  Gilgit  water  supply,  the 
Barmis  water  is  an  accessory  supply  which  drains  into  the  main  channel.  No  case  of 
goiter  has  been  found  among  those  who  use  exclusively  this  Barmis  water. 

ANALYSIS  of  GILGIT  WATERS. 


Supply. 

Total 
solids. 
Parts  per 
100,000. 

Total 
hardness. 
Grams  to 
gallon. 

Calcium. 
Grams  to 
gallon. 

Magne- 
sium. 
Grams  to 
gallon. 

Iron. 
Grams  to 
gallon. 

Sul- 
phates. 
Grams  to 
gallon. 

Chlo- 
rides. 
Grams  to 
gallon. 

Free. 
NH». 

Organic 
matter. 

Other 
metals, 
lead, 
copper, 
zinc. 

Gilgit  

o3o 

7.  143 

6 

Trace. 

Trace. 

Nil. 

Nil. 

Nil 

Barmis  

6  19 

8-10 

Trace. 

Trace. 

3  or  over. 

Nil. 

Nil. 

Nil 

Nil 

21  grams  to  gallon. 


ft  13.3  grams  to  gallon. 


It  is  thus  seen  that  McCarrison's  chemical  evidence  is  negative  in  its  bearing  on  the 
origin  of  goiter.  The  analyses  are  far  from  exhaustive,  but  it  is  to  be  doubted  whether 
greater  detail  would  be  more  significant.  The  much  more  complete  data  which  we 
show  for  waters  associated  with  thyroid  disease  in  fishes  is  as  fruitless  of  any  theory  of 
causation. 

ENDEMIC    OCCURRENCE. 

CALEDONIA    HATCHERY,    N.    Y. 

Studied  from  the  standpoint  of  visible  tumors,  we  found  that  in  certain  hatcheries 
the  disease  is  endemic.  It  is  clear  that  a  large  proportion  of  the  hatcheries  which  main- 
tain Salmonidae  under  conditions  of  domestication  are  more  or  less  affected  by  thyroid 
tumors.  Studied  from  the  standpoint  of  visible  tumors,  the  history  of  the  disease  in  a 
given  hatchery  may  be  traced  backward  in  some  cases  for  several  years,  although  the 
number  of  fish  observed  may  be  small. 

The  oldest  hatchery  in  the  State  of  New  York  is  at  Caledonia.  The  water  supply 
of  this  hatchery  comes  from  springs  located  about  a  mile  distant  from  the  hatchery. 
The  water  supply  is  unusually  ample  and  there  are  maintained  at  this  hatchery  about 
30,000  adult  fish.  Each  year  at  spawning  time  approximately  25  to  50  visible  tumors 
are  found  in  handling  the  fish.  This  condition  has  obtained  for  about  25  years,  being 
within  the  memory  of  the  present  superintendent.  The  fish  are  10,000  rainbow  trout 
and  20,000  brown  trout.  The  brown  trout  are  the  offspring  of  the  first  importation  of 


CARCINOMA   OF  THE   THYROID   IN   SALMONOID   FISHES.  425 


this  variety  into  the  United  States  from  Germany  in  the  eighties.  They  have  been 
tinually  inbred  and  no  fresh  stock  has  been  added.  The  rainbow  trout  have  been  in 
the  hatchery  for  25  years  and  have  not  had  fresh  stock  added  to  them.  Attempts  to 
maintain  the  American  brook  trout  in  this  hatchery  have  been  so  unsatisfactory  as  to 
have  been  abandoned  of  late  years.  This  has  been  partly  due  to  the  prevalence  in  the 
waters  of  the  hatchery  of  a  copepod  parasite  (Lernseopoda)  ,  which  does  not  affect  the 
brown  and  rainbow  trout,  but  is  very  destructive  to  the  brook  trout.  A  few  years  ago, 
however,  200  brook  trout  from  the  annual  hatching  were  raised  to  the  yearling  age  for 
the  purpose  of  exhibition  at  the  State  fair.  In  September,  when  these  fish  were  i^4 
years  old,  they  were  examined,  and  it  was  found  that  every  individual,  with  the  exception 
of  possibly  a  dozen,  presented  visible  tumors,  and  they  were  for  this  reason  discarded. 
It  would  appear  from  this  observation  that  the  brown  and  rainbow  trout  in  this 
hatchery  had  gradually  developed  into  a  more  resistant  strain  than  the  native  brook  trout 
when  introduced  and  maintained  under  the  conditions  affecting  the  hatchery.  That 
this  supposition  is  perhaps  correct  is  shown  by  the  fact  that  at  the  Bath  hatchery  the 
adult  brown  and  rainbow  trout  which  came  from  Caledonia  remained  practically  free 
from  the  disease  during  the  course  of  what  may  be  spoken  of  as  an  epidemic  outbreak 
in  the  latter  hatchery  (p.  77). 

CRAIG    BROOK    STATION:   CONDITIONS    AT  THE   BEGINNING   OP   THE    INVESTIGATION. 

With  the  inauguration  of  a  joint  investigation  by  the  Gratwick  Laboratory  and  the 
Bureau  of  Fisheries,  a  report  of  the  presence  of  thyroid  disease  in  the  various  hatcheries 
of  the  Government  was  obtained,  and  from  among  these  Craig  Brook,  Me.,  was  selected 
for  investigation.  An  examination  at  this  station  made  by  the  superintendent  between 
April  and  May,  1909,  disclosed  in  the  6,695  fish  on  hand  376  with  well-developed  tumors. 
This  hatchery  has  been  under  the  continuous  superintendence  of  Mr.  Charles  G.  Atkins 
for  a  period  of  some  40  years.  It  is  well  equipped  and  at  the  time  of  beginning  our  inves- 
tigation was  particularly  suitable  for  the  work  owing  to  the  unusual  number  of  salmonoid 
species  kept  there  and  the  fact  that  it  was  well  known  as  one  of  the  best  conducted  fish 
cultural  stations  in  the  country.  The  scientific  accuracy  of  its  management  and  the 
unusual  completeness  of  Mr.  Atkins's  records,  which  extended  back  over  a  period  of 
years  and  covered  nearly  every  factor  which  the  progress  of  the  investigation  suggested 
to  us  as  worthy  of  study,  gave  most  unusual  advantages  for  accurate  analysis  of  the 
conditions  under  which  carcinoma  of  the  thyroid  had  developed  here. 

An  investigation  on  the  ground  was  undertaken  by  Dr.  Gaylord,  covering  the  months 
of  July,  August,  and  September.  A  review  of  the  conditions  found  at  Craig  Brook  during 
this  first  summer  is  contained  in  an  unpublished  report  transmitted  to  the  Commissioner 
of  Fisheries  under  date  of  November,  1909,  and  was  reported  during  the  same  month  at 
the  meeting  of  the  American  Association  for  Cancer  Research. 

Our  attention  was  immediately  attracted  to  an  arrangement  of  19  ponds  containing 
yearling  and  2  -year-old  fish.  A  careful  examination  of  all  the  fish  in  these  ponds  during 
the  summer  revealed  the  interesting  fact  that  the  incidence  of  the  diesase  increased 
8207°—  14  -  5 


426 


BULLETIN   OF  THE   BUREAU  OF  FISHERIES. 


from  pond  to  pond  where  these  ponds  communicated  with  each  other.  Figure  76  shows 
the  arrangement  of  the  ponds,  the  general  distribution  of  the  water  supply,  the  species 
of  the  fish,  and  the  incidence  of  the  disease.  The  following  observations  on  this  diagram 
were  made  at  the  time : 


Empty. 


II 


Brook  trout  2  years  old;  lot 
1934 A;    no    visible   evi- 


f 

Empty.                                  | 
1 

1 

Empty.                                    u 

1 

1 

Hybrid  salmon  i  year  old,    i 
lot  1995  ;  5  per  cent  visi-    - 
ble  tumors. 

1 

Hybrid  salmon  i  year  old, 
lot  2017;  no  visible  evi-    L 
dence  of  disease.                  . 

3-     "x^    U  _  J 

dence  of  disease. 

Y*  ,  N 

\ 

/ 

12. 

1 

T 
1 

•  Brook  trout  2  years  old  ;  lot 
I       I939A,  3  per  cent  visible 
1       tumors. 

1 
1 

f 
Empty. 

/-      3     '    x 

.-      4-        > 

\ 

/ 

13.              -/ 
i                      Ji 

.      5        N 

1 

V 

\ 

\ 

s  ( 

* 
V 

t                            |  A                           II     Brook  trout  2  years  old,  lot  1937; 
'                                  r                     —  4j           8.  7  per  cent  visible  tumors. 

| 

Hybrid  salmon  i  year  old,    ' 
lot  1994;  92  per  cent  vis-    f1 
ible  tumors. 

-      6         > 

, 

r                      //  Brook  trout  2  years  old,  lot  1939;  13 
,'                        1*).             —-It          per  cent  visible  tumors. 

1 

i 

I 

/ 

almon  i  year  old,  lot  1986;  84 
ible  tumors. 

1 

Empty.                                    1- 
1 

-       1 

_j 

\ 

t                   \C.                Ji    Humpback  s 
S                     •"'         ~~r         per  cent  vis 

A 

1 

\ 
\ 

N. 

/ 

L 

Empty.                                    | 
I 

Z       ^ 

1. 

f 

1  Scotch  sea  trout  2  years  old,  lot  1947;  no  visible 
0                  i*«                       evidence  cf  disease. 

~ 

1 

landlocked  salmon,  2  years  1 
old,  lot  1944;  no  visible  L 
evidence  of  disease. 

9 

Scotch  sea  trout  2  years  old,  lot  I947A;  no  vis- 
tf                  J  8.        —         ible  evidence  of  disease. 

1 

landlocked  salmon,  2  years  1 
old,  lot  1950;  24  per  cent  r 
visible  tumors. 

10           >> 

/ 

f*                 j  Q         —  .     Empty. 

FIG.  76. — Plan  of  south  ponds  at  Craig  Brook  station. 


The  water  supply  of  ponds  i  to  1 1  is  from  a  natural  spring  on  the  hillside.  The 
water  supply  of  ponds  2  to  10  and  12  to  19  is  from  Craig  Brook,  the  water  of  each  pond  for 
the  most  part  flowing  into  the  pond  immediately  below  it,  pond  n  flowing  into  pond  12. 
As  the  diagram  shows,  pond  n  contained  healthy  fish.  These  up  to  the  time  of  this 


CARCINOMA   OF  THE   THYROID   IN   SALMONOID   FISHES.  427 

observation  had  not  been  fed  artificial  food  but  had  found  a  sufficient  supply  of  natural 
food  in  the  grass-lined  pond  they  occupied.  Lot  1939  A,  230  two-year-old  brook  trout, 
and  lot  1939,  132  two-year-old  brook  trout,  were  hatched  from  the  same  lot  of  eggs, 
divided  and  placed  in  their  respective  ponds  during  the  summer  of  1908.  They  were 
comparable  in  every  respect  except  their  location  in  the  ponds,  the  feeding  for  all  the 
lots  being  the  same,  i.  e.,  raw  liver.  Lot  1939  A  occupied  pond  12  next  to  the  uppermost 
pond;  1939,  pond  15,  three  ponds  below.  The  chart  shows  that  1939  A  showed  3  per 
cent  of  visible  tumors,  being  the  lowest  incidence  of  any  lot  affected,  1939  15  per  cent. 
Between  these  ponds  lot  1937  in  pond  14,  also  2-year-old  brook  trout,  gave  an  incidence  of 
8.7  per  cent.  Lot  1986,  humpback  salmon,  were  yearling  fish  and  in  common  with  the 
hybrid  salmon,  lot  1994  of  the  same  age,  showed  the  highest  incidence  of  any  of  the 
lots,  namely,  84  and  92  per  cent.  Lot  1950,  two-year-old  landlocked  salmon  in  pond  10, 
were  the  least  favorably  placed  2 -year-old  fish  and  showed  the  highest  incidence  for  this 
age,  24  per  cent.  (Fig.  4b.) 

Here  we  may  plainly  see  that  the  incidence  of  the  disease  increases  from  above 
downward  in  the  ponds,  both  in  the  2-year-old  and  the  yearling  fish.  The  deduction 
may  also  be  drawn  from  the  conditions  found  in  these  ponds  that  the  incidence  of  the 
disease  is  greater  in  the  yearling  fish  than  in  the  2-year-old,  but  subsequent  observations 
indicate  that  other  factors,  such  as  the  species  heredity  and  hybridization,  may  so 
markedly  affect  the  susceptibility  that  this  material  is  not  suitable  for  such  deduction. 
(See  p.  82.) 

Perhaps  the  most  striking  feature  of  this  diagram  is  the  evidence  it  affords  of  im- 
munity in  certain  species  and  certain  lots.  The  2-year-cfld  Scotch  sea  trout,  lots  1947 
and  1947  A,  were  found  on  examination  to  present  no  visible  tumors  and  it  was  con- 
cluded that  they  were  immune  to  the  disease,  a  fact  which  microscopic  examination  and 
further  observation  has  confirmed.  The  2-year-old  landlocked  salmon,  lot  1944,  occupy- 
ing pond  9,  although  placed  below  the  yearling  hybrid  lot,  1994,  in  pond  6,  were  also 
free  from  the  disease,  although  the  2-year-old  landlocked  salmon,  lot  1950,  immediately 
below  them  in  pond  10,  showed  the  highest  incidence  of  the  disease  in  2 -year-old  fish. 
Yearling  hybrid  salmon,  lot  2017,  were  also  free  from  the  disease  and  in  accordance 
with  the  general  scheme,  the  smallest  incidence  in  susceptible  hybrid  salmon,  lot  1995 
in  pond  4,  is  found  in  the  uppermost  pond.  The  further  histories  of  the  hybrid  lots 
and  the  immune  fish  are  traced  in  the  observations  of  the  succeeding  years. 

An  attempt  was  made  to  trace  the  history  of  these  fish  from  the  time  they  were 
hatched  in  the  hatchery  through  the  various  troughs  which  they  occupied  at  different 
periods  up  to  the  time  of  their  final  location  in  these  ponds.  The  records  pertaining 
to  the  various  lots  covered  the  origin  of  the  eggs,  the  time  of  hatching,  the  mortality 
at  every  stage  of  their  history  in  the  hatchery,  the  temperature  of  the  water  taken  three 
times  daily,  and  exact  data  as  to  the  feeding,  when  first  begun,  and  the  amounts  fed. 
While  it  was  impossible  to  determine  the  exact  troughs  in  which,  or  the  exact  time  when, 
the  fish  might  have  contracted  the  disease,  yet  our  attention  was  finally  fixed  upon  a 


428  BULLETIN  OF  THE  BUREAU  OF  FISHERIES. 

group  of  wooden  troughs  which  the  records  showed  had  been  previously  occupied  by 
the  fish  that  were  now  affected  in  the  ponds.  In  October,  1909,  these  troughs  were  occu- 
pied by  small  fish  hatched  the  preceding  spring,  and  from  one  of  the  troughs  a  small 
brook  trout,  a  so-called  fingerling,  was  found  dead  and  proved  on  examination  to  have  a 
protruding  visible  tumor  in  the*  thyroid  region.  (See  fig.  73.)  On  microscopic  examina- 
tion this  was  found  to  be  tubulo-alveolar  solid  carcinoma,  infiltrating  the  surrounding 
structures.  (See  fig.  64.) 

These,  in  the  main,  are  the  facts  which  were  impressed  upon  us  by  the  undisturbed 
conditions  at  Craig  Brook.  The  observations  of  the  following  summers  were  carried 
out  on  a  more  extensive  basis. 

CRAIG    BROOK    STATION:    CONDITIONS   DURING   THREE   YEARS. 

The  Craig  Brook  fish  cultural  station  (fig.  77)  of  the  United  States  Bureau  of 
Fisheries  is  located  on  Lake  Alamoosook  about  i  mile  from  East  Orland,  Hancock  Co., 
Me.  It  is  but  a  few  feet  above  tidewater.  The  station  was  established  in  1879  for 
the  artificial  propagation  of  trout  and  salmon,  though  Atlantic  salmon  eggs  were  first 
hatched  there  in  1871-2.  It  is  well  provided  with  troughs  in  hatchery  buildings  for 
the  incubation  and  hatching  of  eggs,  with  troughs  out  of  doors  for  the  rearing  of  young 
fish,  and  with  earthen  ponds  for  holding  older  fish  and  adults.  Craig  Pond  drains 
into  Lake  Alamoosook  through  Craig  Brook,  the  whole  flow  of  which  is  intercepted  for 
fish-cultural  purposes.  A  small  quantity  of  spring  water  is  also  available  for  the  station 
supply. 

Fish  culture  at  Craig  Brook  has  been  chiefly  concerned  with  brook  and  rainbow 
trout,  the  Scotch  sea  trout,  landlocked  salmon,  and  with  hybrid  trout  and  hybrids  of 
some  Pacific  salmon.  Investigations  of  thyroid  disease  among  the  fish  were  first  made 
in  1909,  as  above  stated,  and  have  been  continued  more  or  less  to  date,  especially  during 
the  summer  months.  Thyroid  carcinoma  was  immediately  found  endemic  at  the 
station,  and  affected  every  salmonoid  species  or  hybrid  except  the  Scotch  sea  trout, 
which  is  almost  immune,  and  the  chinook  salmon. 

The  system  of  outside  ponds  holding  adult  fish  at  Craig  Brook  station  is  shown  in 
figure  78  (p.  429),  and  has  been  already  referred  to.  A  more  exact  study  of  the 
water  supply  shows  that,  with  two  "exceptions,  these  19  ponds  receive  brook  water  and 
in  part  discharge  into  each  other  from  the  upper  to  the  lower.  Pond  i ,  however,  re- 
ceives only  spring  water,  which  is  discharged  into  pond  1 1  and  thence  drains  independ- 
ently of  all  others.  The  rest  of  the  ponds  are  each  supplied  in  part  with  fresh  brook 
water  and  in  part  with  this  water  after  it  has  flowed  through  preceding  ponds  in  the 
series.  The  ponds  are  entirely  of  earth  and  some  have  small  quantities  of  higher 
plant  life,  besides  harboring  abundant  growths  of  filamentous  green  algae  during  the 
summer  months.  Ponds  i  and  n  are  best  supplied  with  vegetation.  (Fig.  80.) 


CARCINOMA   OF  THE  THYROID   IN   SALMONOID   FISHES, 
f  Spring 


4?9 


FIG.  78. — Plan  of  ponds,  Craig  Brook  station,  showing  water  supply. 


43°  BULLETIN   OF  THE  BUREAU  OF  FISHERIES. 

In  this  pond  system  trout  and  salmon  and  hybrid  trout  and  salmon,  of  various 
adult  ages  and  sizes  and  of  various  species,  were  held  under  ordinary  fish-cultural  con- 
ditions, varied  to  a  slight  extent  for  experimental  purposes,  during  some  three  years. 
Nearly  all  were  examined  each  summer  for  four  consecutive  years.  Thyroid  disease 
was  seen  among  them  in  all  degrees  of  severity  up  to  large  visible  carcinomata,  and  with 
greatly  varying  incidence  from  all  but  complete  immunity  to  macroscopic  involvement 
of  more  than  90  per  cent  of  the  individuals  of  a  given  pond  lot. 

The  physical  conditions  in  these  ponds  were  those  common  to  intensive  breeding 
of  trout.  All  the  factors  of  crowding,  artificial  food,  reduced  water  supply,  and  accumu- 
lation of  waste  products,  as  compared  with  conditions  under  which  trout  live  in  a  wild 
state,  were  present  in  greater  or  less  degree.  But  the  reaction  of  the  fish  to  these  con- 
ditions, as  expressed  by  the  macroscopic  evidence  of  the  thyroid  disease,  was  by  no 
means  uniform  but  varied  within  wide  limits. 

It  is  of  interest  to  consider  more  in  detail  the  external  evidence  of  thyroid  growth 
in  these  fish  over  a  term  of  years.  The  identity  of  a  given  lot  of  fish  is  preserved  by  a 
number.  Visibly  affected  fish  are  those  showing  any  macroscopic  indication  of  abnormal 
thyroid  growth  from  the  red  floor  upward.  Visible  tumors  refer  to  those  showing 
definite  tumors.  It  will  be  noticed  that  the  loss  on  the  lots  from  year  to  year  is  in  most 
cases  considerable.  This  of  course  is  not  to  be  charged  entirely  to  thyroid  disease, 
either  directly  or  indirectly.  Besides  intercurrent  disease,  many  fish  are  lost  by  depre- 
dations of  predatory  birds  and  animals,  and  it  is  impossible  for  obvious  reasons  to 
apportion  the  total  loss  quantitatively  among  these  separate  factors. 

Table  IV  summarizes  the  condition  of  each  lot  at  the  summer  examination  during 
three  or  four  years,  and  gives  the  percentage  of  loss.  The  tumor  fish  were  permanently 
removed  at  each  examination,  unless  otherwise  stated.  The  fish  with  red  floors  only 
were  not  so  removed. 

In  pond  i  were  placed,  in  August,  1909,  119  2-year-old  landlocked  salmon  (1950  T), 
all  bearing  visible  tumors.  They  were  taken  from  lot  1950.  They  were  fed  proteid 
artificially  until  February,  1910,  and  thereafter  received  only  such  food  as  the  pond 
naturally  afforded.  A  large  measure  of  recovery  occurred  (p.  87).  After  one  year 
nearly  half  the  visible  tumors  had  disappeared.  The  next  year  only  two  fish  were 
left  and  the  experiment  was  abandoned.  In  August,  1909,  28  2-year-old  clinically 
clean  brook  trout  were  present  in  pond  1 1 ,  and  the  annual  remnant  has  remained  clean 
ever  since.  The  conditions  in  these  two  ponds,  which  are  separate  from  the  rest  of  the 
series,  were  discussed  on  page  68.  The  only  water  supply  of  pond  1 1  came  from  pond  i , 
which  contained  at  the  beginning  only  tumored  fish,  and  the  fish  in  pond  1 1  regularly 
received  artificial  food. 

Ponds  2,  12,  and  19  receive  only  unused  brook  water,  while  nearly  all  the  remaining 
ones  receive  the  greater  part  of  their  supply  from  the  next  pond  above  and  the  lesser 
part  direct  from  the  brook.  Pond  4  had  in  August,  1909,  146  yearling  hybrid  salmon, 
lot  1995  (female  humpback  and  male  blueback)  with  5  per  cent  of  visible  tumors,  which 
were  left  with  the  clean  fish.  The  next  year  there  were  9  per  cent  and  the  following  year 
none,  though  the  total  affected  fish  had  reached  37  per  cent. 


CARCINOMA   OF  THE  THYROID  IN   SALMONOID   FISHES. 


431 


Pond  5  in  August,  1909,  contained  lot  2017,  consisting  of  729  yearling  hybrids 
(female  brook  trout  and  male  landlocked  salmon),  all  clean  fish.  These  were  the 
survivors  of  1,553  fish  °f  the  previous  April,  all  of  which  were  clean  at  that  time.  This 
lot  was  almost  immune  for  two  years.  Only  13  red  floors  and  2  tumors  were  produced 
in  one  year.  The  next  year  all  of  the  remaining  fish  were  clean,  and  finally  in  1912 
there  were  10  tumored  fish  among  the  220  remaining. 

In  pond  6  were  placed,  in  August,  1909,  469  yearling  chinook  salmon.  This  pond 
previously  contained  lot  1994,  badly  affected  hybrid  salmon.  During  the  two  years 
in  which  these  chinook  salmon  were  kept  under  observation  no  visible  thyroid  process 
was  produced.  This  species  (Oncorhynchus  tschawytscha)  is  a  Pacific  salmon,  an 
anadromous  marine  fish.  In  no  adult  marine  salmon  have  we  seen  thyroid  disease. 
Humpback  salmon  yearlings  in  troughs  of  fresh  water  at  the  hatchery  acquired  a  heavy 
tumor  involvement. 

Ponds  7  and  8  contained  in  July,  1910,  147  clean  yearling  rainbow  trout  (lot  2133). 
No  visible  tumors  have  been  produced.  After  one  year  3  per  cent  had  red  floors  and 
after  two  years  only  2  fish  of  the  31  remaining  had  the  incipient  process. 

Pond  9  held,  in  August,  1909,  97  clean  2-year-old  landlocked  salmon.  They 
remained  clean  during  the  first  year.  In  July,  1911,  there  were  10  per  cent  of  red  floors, 
but  no  visible  tumors.  In  August,  1912,  there  were  but  32  fish  left,  of  which  i  had  a 
red  floor  and  i  a  tumor  and  red  floor. 

Pond  10  is  the  lowermost  of  the  first  row  of  ponds  and  is  almost  entirely  supplied 
by  previously  used  water.  In  August,  1909,  the  673  clean,  2 -year-old  landlocked  salmon 
remaining  after  the  removal  of  219  tumored  fish  from  lot  1950  were  placed  in  this 
pond.  The  loss  was  not  excessive  on  this  lot.  By  July,  1911,  7.7  per  cent  had  visible 
tumors  while  37  per  cent  were  affected,  the  fish  having  reached  4  years  of  age.  Thus 
the  tumor  fish  of  this  lot  recovered  under  more  natural  conditions  in  pond  i ,  while  the 
remainder  continued  to  develop  tumors  under  the  intensive  conditions  of  pond  10. 

Pond  12  receives  30  gallons  per  minute  of  unused  brook  water  only.  In  August, 
1909,  7  tumored  fish  were  removed  from  the  2-year-old  brook  trout  of  lot  1939  A 
and  the  223  clean  fish  were  left  in  pond  12.  In  July,  1910,  but  80  fish  remained,  of 
which  5  per  cent  were  affected,  including  but  one  tumor.  In  1911,  5  per  cent  had 
tumors  and  25  per  cent  were  affected.  In  1912  the  remaining  58  fish  had  a  slight 
increase  in  both  respects. 

Pond  13  contained  cyprinoid  fish,  which  do  not,  so  far  as  observed,  acquire  thyroid 
tumors  or  any  notable  thyroid  changes,  and  are  not  considered  in  the  present  study. 
Pond  14  contained  in  August,  1909,  167  clean  2-year-old  brook  trout  remaining  after 
the  removal  of  16  tumored  fish  from  lot  1937.  During  the  next  year  the  thyroid  process 
progressed  rapidly,  15  per  cent  acquiring  tumors  and  31  per  cent  becoming  affected. 
During  the  next  year  there  was  a  very  definite  regressive  process,  and  during  the  last 
year,  the  fish  reaching  5  years  of  age,  there  was  again  a  slight  progression.  Pond  15 
had  similar  susceptible  fish,  the  process  continuing  slowly  at  first  and  then  more  rapidly. 

Ponds  17  and  18  contain  Scotch  sea  trout,  which  are  of  especial  interest  and  impor- 
tance. These  ponds  receive  almost  entirely  previously  used  brook  water,  and  the 


432  BULLETIN   OP  THE  BUREAU  OF  FISHERIES. 

essential  fish  cultural  factors  are  among  the  most  pronounced  of  all  the  ponds.  The 
immunity  of  this  species  is  apparently  not  quite  impregnable.  One  case  of  supposed 
small  incipient  tumor  was  lost  by  accident  before  a  proper  examination  of  it  could  be 
made.  Several  fish  with  definite  red  floors  have  been  observed,  but  these  are  cases  of 
colloid  goiter  rather  than  the  hyperplastic  stages  comparable  to  those  of  the  susceptible 
species. 

At  Craig  Brook  station  many  unpainted  wooden  troughs  established  out  of  doors 
are  used  for  holding  and  rearing  young  fish  until  they  are  large  enough  to  demand 
transfer  to  ponds.  They  are  each  about  3.1  meters  long,  by  32  centimeters  wide  and 
23  centimeters  deep.  (Fig.  79.)  They  are  supplied  by  brook  water,  in  part  from  the 
hatchery  building  with  water  which  had  flowed  through  the  hatchery  troughs,  and  in  part 
freshly  from  Craig  Brook.  The  water  supply  of  these  outside  troughs  flows  from  one 
trough  to  the  other  among  some  of  the  series  of  troughs.  Troughs  93  to  104,  however, 
shown  in  table  v,  receive  water  immediately  from  the  hatchery.  Fish  are  not  usually 
held  in  these  wooden  troughs  beyond  the  first  year,  but  in  those  of  table  v  they  have 
been  continued  beyond  the  third  year  for  experimental  results  with  thyroid  disease  in 
these  surroundings.  The  fish  were  fed  the  regular  artificial  food,  chiefly  liver,  and  were 
in  general  subjected  to  the  usual  artificial  conditions,  the  space  available  and  the  water 
supply  being  less  than  the  earth  ponds  of  table  iv  would  have  afforded.  This  series  of 
troughs  was  chosen  because  they  were  the  containers  of  the  young  fish  which  later 
showed  the  most  visible  tumors,  and  from  one  of  them  (no.  92)  was  obtained  the  5-months- 
old  brook  trout  with  a  tumor  of  considerable  size,  the  youngest  fish  yet  found  with  a 
visible  thyroid  tumor.  Entirely  uniform  conditions  obtained  in  these  troughs.  They 
were  of  the  same  size  and  shape,  supplied  by  the  same  water,  subject  to  the  same  regime, 
and  afford  the  opportunity  for  comparable  experiments. 

It  is  seen  that  during  these  three  years  the  brook  trout,  landlocked  salmon,  and 
various  hybrids  show  progressively  increasing  thyroid  growth  from  year  to  year.  Fish 
with  visibly  affected  thyroids  not  reaching  to  tumor  formation  are  much  more  numerous 
from  the  beginning  than  those  with  visible  tumors.  The  latter  often  appear  among 
the  yearlings,  but  the  chief  incidence  is  among  2  and  3  year  olds.  The  Scotch  sea  trout 
are  exceptional  and  show  a  pronounced  resistance  here  as  in  the  earth  ponds.  No 
visible  tumors  appear  during  the  three  years.  Out  of  some  300  fish  the  second  year,  2 
only  show  the  incipient  hyperemia  of  the  floor  of  the  mouth,  and  in  the  third  year  i 
more.  These  trout  were  plainly  exposed  to  exactly  the  same  conditions  "'which  result 
in  large  percentages  of  tumor  involvement  in  other  species.  Their  resistance  amounts 
to  practical  immunity. 

In  neither  the  earth  ponds  nor  the  wooden  troughs  are  the  observations  sufficient 
to  establish  anything  but  the  general  conditions  of  fish  culture  or  domestication,  under 
which  thyroid  disease  progresses.  None  of  the  specific  factors  of  which  domestication 
consists  have  been  or  can  be  isolated  in  this  way.  It  is  plain,  nevertheless,  that  earth 
ponds  are  unnecessary  to  the  disease.  The  wooden  troughs  are  easily  kept  clean  and 
do  not  become  fouled  for  long  by  the  accumulation  of  the  products  of  the  fish  and 


CARCINOMA   OP  THE   THYROID   IN   SAI^MONOID   FISHES.  433 

the  unused  food.     The  material  of  the  trough,  though  water-soaked,  affords  no  perma- 
nent lodgment  for  gross  particles  of  organic  matter. 

Since  thyroid  carcinoma  in  fishes  is  rare  in  nature  and  common  in  domestication  it 
would  seem  that  some  or  all  of  the  conditions  of  domestication — artificial  propagation 
of  fish — either  by  their  own  direct  action  cause  the  disease,  predispose  to  it,  or  carry 
its  cause  to  the  fishes.  That  domestication  itself,  viewed  as  a  single  complex  whole, 
is  per  se  the  cause  of  thyroid  disease,  is  a  priori  highly  improbable,  and  is  negatived 
by  the  occurrence  of  thyroid  tumors  in  wild  fish.  This  occurrence,  though  sporadic 
and  rare,  is  now  established  beyond  dispute  and  is  a  fact  of  great  significance.  Domesti- 
cation predisposes  to  the  disease  and  carries  the  causative  agent  to  the  fishes,  and  some 
one  or  very  few  of  the  constituent  factors  or  conditions  of  domestication  is  probably 
of  chief  importance  in  this  action.  From  a  study  of  the  conditions  at  such  a  station  as 
Craig  Brook,  while  the  disease  is  spontaneous  and  endemic  under  the  routine  of  fish 
culture,  it  is  difficult  to  fix  accurately  upon  any  one  of  these  conditions  to  the  exclusion 
of  others  as  the  prime  essential.  Feeding  is  probably  more  important  than  any  other 
one  factor.  The  removal  of  feeding  or  change  to  natural  food  tends  toward  the  recovery 
of  affected  fishes,  and  prevents  or  delays  the  initial  process.  The  inevitable  reduction 
in  the  available  unit  of  water  supply  per  fish  and  the  crowding  of  fish  together  in  small 
areas  are  no  doubt  factors  of  next  importance.  We  do  not  believe  that  the  soluble 
products  of  metabolism  and  of  the  disintegration  of  organic  matter  left  from  feeding 
or  otherwise  play  any  important  part  in  the  origin  or  progress  of  this  disease,  unless 
as  creating  more  favorable  conditions  for  the  development  of  a  causative  agent.  An 
unfavorable  general  hygiene  of  the  fish  predisposes  to  the  disease,  domestication  itself 
as  usually  practiced  involving  a  more  or  less  unfavorable  hygiene,  and  in  this  way 
these  soluble  products  may  enter  somewhat  into  the  problem  of  causation. 


434 


BULLETIN  OF  THE  BUREAU   OP  FISHERIES. 


TABLE  IV. — INCIDENCE  ov  THYROID  CARCINOMA  IN  DIRT  PONDS,  CRAIG  BROOK,  1909-1912. 

[Where  there  are  two  entries  for  August,  1909.  under  total  number  of  fish,  the  number  before  and  after  removal  of  tumored 
fish  is  indicated.] 


Pond 

No. 

Lot  No. 

Date. 

Age. 

i 
Species. 

Total 
number 
fish. 

Visibly 
affected. 

Visible 

tumors. 

Loss. 

Years. 

Per  cent. 

Per  cent. 

Per  cent. 

do        

39 

56.  o 

.do  

a 

50.  o 

.  o 

8s-  7 

(          M2 

(?) 

5-5 

" 

do 

I          138 

.0 

.0 

do      

Hybrids  &  

July,  1910 

...do  

543 

3-o 

do        

.do  

6 

Aug.,  1909 

Chinook  salmon  

469 

July,  1910 

...do...   

•  O 

July,  1911 

do  

53 

.0 

•  o 

76.  9 

July,  1910 

Rainbow  trout  

July,  1911 

..  do  

8 

July,  1910 

....do  

70 

8 

July,  1911 

....do  

46 

.0 

7-8 

Aug.,  1912 

do            

6.4 

July,  1910 

...do  

73 

July,  1911 

4 

do  

66 

.0 

Aug.,  1912 

5 

do  

32 

6.2 

3.  i 

10 

Aug.,  1909 

do  

(     2" 

(?) 

24-5 

July,  1910 

do... 

\     673 
6<>o 

.0 

.0 

July,  1911 

.do  

II 

Aug.   1909 

Brook  trout  

S8? 

July,  1910 

...do... 

65 

(?) 

July,  1911 

...do.... 

28 

Aug.,  1912 

5 

do  

8 

13 

Aug.,  1909 

do  .     .               

/          230 

(?) 

3-0 

July,  1910 

.do  

\          223 

80 

.0 

.0 

July,  1911 

...do  

80 

Aug.,  1912 

do  

58 

do 

/          183 

(?) 

8-7 

July,  1910 

...do... 

I          167 
76 

.  o 

.0 

July,  1911 

do  

c  6 

6  6 

Aug.,  1912 

do  

.0 

15 

Aug.,  1909 

....do  

/           133 

(?) 

iS-o 

July,  1910 

...do... 

1           "3 

.  o 

6    7 

.0 

July,  1911 

...do... 

8  8 

Aug.,  1912 

5 

do  

17 

Aug.,  1909 

Scotch  sea  trout 

5 

July,  1910 

....do  

1 

' 

July,  1911 

...do... 

18 

16  T 

' 

Aug.,  1912 

5 

...do... 

' 

* 

18 

i94?A  

Aug..  1909 

...do... 

July,  1910 

3 

do  

1  88 



July,  1911 

4 

do  

*        .g 

Aug.,  19:2 

5 

do  

6.0 

°  Female,  humpback;  male,  blueback. 


fr  Female,  brook  trout;  male,  landlocked  salmon. 


CARCINOMA  OF  THE  THYROID  IN  SALMONOID  FISHES.  435 

TABLE  V. — INCIDENCE  OF  THYROID  CARCINOMA  IN  WOODEN  TROUGHS,  CRAIG   BROOK,  1910-1912. 


Trough 
No. 

Lot  No. 

Date. 

Age. 

Species 

Total 
fish. 

Visibly 
affected. 

Visible 
tumors. 

Loss. 

\~tar 

Brook  trout  

Number. 
59 

Per  cent. 
28.0 

Per  cent. 

Per  cent. 

..   ..do  

35 

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o  Many  fish  used  in  experiments. 
LAKE    AUBURN    HATCHERY,  MAINE. 

This  is  a  State  hatchery  in  Androscoggin  County.  In  August,  1910,  an  examination 
of  fish  for  visible  tumors  was  made  and  the  general  conditions  inspected.  Pond  i  was 
a  dirt  pond  fed  by  two  springs  of  water  very  cold  at  its  origin,  and  standing  at  11°  C. 
in  the  pondon  August  20.  The  spring  water  has  a  very  low  content  of  dissolved  matter 
and  is  said  to  have  about  the  same  analysis  as  the  well-known  Poland  Springs  of  Maine. 
The  pond  held  nearly  400  brook  trout  of  3^  years  of  age,  which  had  occupied  the  pond 
since  the  yearling  stage.  They  had  been  fed  raw  beef  liver  until  a  year  old  and  raw 
beef  heart  ever  since.  The  fish  were  raised  from  eggs  from  the  local  station  and  from 
domesticated  eggs  obtained  from  Michigan.  They  were  apparently  in  fine  condition, 
were  feeding  well,  and  had  suffered  but  little  loss.  One  hundred  and  thirty-one  of  these 
trout  were  examined,  of  which  20.5  per  cent  showed  visibly  diseased  thyroids  and  5.3 
per  cent  of  the  131  bore  visible  tumors. 

Pond  2  was  a  similar  dirt  pond,  fed  from  six  independent  springs  and  sometimes 
by  the  overflow  of  pond  i.  Its  water  was  warmer,  being  15.5°  C.  It  held  4-year-old 
brook  and  brown  trout  and  adult  landlocked  salmon.  A  seine  haul  of  fish  were  exam- 
ined. Of  66  brook  trout,  21.5  per  cent  had  visible  tumors  and  19.5  per  cent  red  floors; 
of  15  salmon,  i  had  a  red  floor  and  4  had  visible  tumors;  of  36  brown  trout  all  were 
entirely  clean,  without  external  sign  of  thyroid  proliferation.  The  food  was  beef  heart. 
There  was  no  marked  mortality  rate,  but  there  was  a  heavy  loss  on  spawn  taken  from 
the  fish  of  this  pond. 


436  BULLETIN  OP  THE  BUREAU  OF  FISHERIES. 

Of  a  large  number  of  yearling  landlocked  salmon  held  in  a  small  pond,  102  were 
examined.  Seven  fish  were  affected,  three  having  red  floors  and  four  visible  tumors. 

There  is  nothing  extraordinary  about  the  conditions  at  Lake  Auburn  hatchery,  which 
shows  rather  a  typical  case  of  the  endemic  occurrence  of  the  disease.  Here  are  spring 
water,  dirt  ponds,  the  common  proteid  foods,  liver  and  heart,  and  adult  fish  in  excellent 
condition  from  the  ordinary  fish  cultural  standpoint,  and  with  no  unusual  mortality 
rate,  but  a  considerable  morbidity  in  visible  thyroid  enlargement,  with  immunity  of 
the  brown  trout. 

At  two  other  State  hatcheries  similar  or  greater  morbidity  has  been  determined 
from  actual  examination,  and  reports  from  superintendents  of  both  Federal  and  State 
hatcheries  indicate  the  general  extent  to  which  these  conditions  obtain,  with  some  few 
exceptions,  throughout  the  territory  of  trout  culture  in  the  United  States. 

PRIVATE   HATCHERY   IN   THE   STATE   OF   WASHINGTON. 

At  North  Yakima,  Wash.,  an  interesting  and  instructive  example  is  afforded  of 
endemic  occurrence  among  young  trout  at  a  newly  established  private  hatchery  where 
30,000  brook  trout  were  held  in  earth  trenches  supplied  by  spring  water.  The  food  for 
the  first  six  months  was  liver,  after  that  horse  meat.  The  hatchery  was  started  in 
March.  In  the  following  December,  before  the  trout  were  a  year  old,  thyroid  tumors 
were  observed  among  them,  about  i  per  cent  being  affected.  The  several  specimens 
we  have  examined  show  tumors  which,  relative  to  the  size  of  the  fish,  are  among  the 
largest  we  have  seen.  One  of  these  was  13  millimeters  in  diameter  in  a  trout  8.5  centi- 
meters in  standard  length.  Microscopically  the  structure  shows  solid  carcinoma, 
among  the  most  malignant  of  our  examples. 

Rainbow  trout  of  the  same  age  and  living  under  exactly  the  same  conditions  at 
this  hatchery  are  not  affected  with  thyroid  tumors.  The  region  in  this  part  of  the 
State  is  said  to  show  a  high  percentage  of  goiter  among  female  children  and  among  calves 
and  other  domestic  animals.  Statistical  studies,  however,  have  not  been  made. 

This  instance  shows  an  unusual  acceleration  of  the  thyroid  process.  Malignant 
carcinoma  of  large  size  developed  in  trout  under  i  year  of  age  and  during  the  first  year 
of  a  fish  hatchery.  Obviously  domestication  of  long  duration,  either  in  the  individual 
fish  or  in  the  local  station  where  the  fish  are  held,  is  unnecessary.  Something  local  at 
this  particular  fish  hatchery  seems  to  be  concerned  in  the  unusual  result.  Certainly 
the  general  conditions  of  trout  culture  as  expressed  at  the  numerous  stations  where 
trout  are  bred  do  not  result  in  the  rapid  course  of  disease  here  shown.  Is  there  merely 
a  local  intensification  at  this  hatchery  of  the  essential  cause  of  the  disease? 

EPIDEMIC  OCCURRENCE. 

"The  hatchery  at  Bath,  N.  Y.,  referred  to  in  the  introduction  as  having  first 
attracted  our  attention  to  this  condition,  was,  up  to  1907,  free  from  visible  tumors. 
From  the  accompanying  diagram  (fig.  81)  it  will  be  seen  that  the  water  supply  of  this 
hatchery  comes  from  a  large  pond  (A)  fed  by  several  springs  on  land  adjoining  the  hatch- 


CARCINOMA  OF  THE  THYROID   IN  SALMONOID  PISHES. 


437 


438  BULLETIN  OF  THE  BUREAU  OP  FISHERIES. 

ery,  and  many  larger  and  smaller  springs  in  the  pond  itself,  and  that  this  supplies  the 
greater  portion  of  the  water  to  the  hatchery.  This  water  is  supplemented  by  a  large 
spring  B,  forming  one  system  of  water  supply,  while  the  water  from  springs  C  and  F 
forms  the  other,  the  two  systems  uniting  in  race  12.  The  water  coming  from  the  large 
pond  is  aerated  in  fountains  K  and  L.  Springs  D  and  E  tap  a  vein  running  in  a  northerly 
direction  at  a  depth  of  about  15  to  25  feet.  The  water  from  these  two  springs  is  now 
used  exclusively  in  the  hatchery  building  for  hatching  this  season's  spawn.  The  large 
pond  A  maintained  in  1907  an  unknown  number  of  fish  living  under  wild  conditions, 
being  fish  which  from  time  to  time  were  placed  in  the  pond,  where  they  had  then  shifted 
for  themselves.  The  pond  is  grass-grown  about  the  banks,  has  a  plentiful  growth 
upon  its  bottom,  and  presents  practically  an  ideal  approach  to  wild  conditions.  (Fig.  82.) 

In  1906  a  brown  trout  approximately  2  years  old  was  found  dead  at  the  outlet 
of  the  big  pond,  and  on  examination  presented  two  well-developed  tumors  at  the  junc- 
tion of  the  gills.  This  was  the  first  evidence  of  the  disease  which  the  superintendent 
had  noted.  In  September,  1907,  pond  A  was  emptied,  a  large  portion  of  the  fish  in  it 
escaping  into  the  brook.  After  cleaning  the  bottom,  removing  the  grass,  etc.,  the 
pond  was  stocked  with  about  6,000  brook  trout  fry  hatched  in  the  hatchery,  and  sys- 
tematic feeding  with  liver  was,  for  the  first  time,  practiced  in  this  pond.  From  August 
to  October,  1908,  a  few  of  the  yearling  fish  in  the  large  pond  were  found  dead  with  visi- 
ble tumors.  In  October  the  fish  in  the  lower  races  supplied  from  the  big  pond  also  began 
to  die  in  sufficient  numbers  to  attract  attention,  and  a  large  proportion  of  these  were 
found  also  to  have  visible  tumors.  During  the  summer  of  1908  not  less  than  3,000  fish, 
exclusively  brook  trout,  died  in  this  hatchery  with  visible  tumors.  During  this  period 
of  the  outbreak  some  1 75  adult  rainbows  held  in  one  of  the  lowermost  ponds,  to  which 
ran  the  water  from  the  spring  running  through  the  races  seriously  affected,  remained 
free  from  the  disease,  with  the  exception  of  i  fish  found  late  in  the  season.  Some 
4,000  yearling  brown  trout  from  Caledonia  remained  free  from  evidence  of  visible 
tumors,  as  did  also  some  220  four-year-old  brown  trout  from  the  same  source. 

During  the  summer  of  1909  epidemic  conditions  obtained  in  this  hatchery  in  more 
aggravated  form  than  in  any  previous  year.  The  stock  fish  as  well  as  the  fry  were  fed 
almost  exclusively  on  beef  livers,  obtained  twice  a  week  from  the  Buffalo  abattoirs.  A 
large  proportion  of  this  liver  fell  to  the  bottom  of  the  large  pond  and  there  decayed. 
The  food  not  eaten  up  in  the  races  was  brushed  out  frequently  enough  to  prevent  con- 
tamination. About  200  pounds  of  beef  livers  were  fed  weekly  in  the  hatchery.  A 
number  of  times  livers  were  found  with  large  single  or  multiple  abscesses. 

The  stock  fish  in  the  hatchery  in  1 909  consisted  of  the  following,  some  lots  of  which 
may  be  recognized  as  having  figured  in  the  occurrences  in  the  hatchery  of  1908 — 125  to 
150  rainbows  held  in  concrete  race  13;  3,000  two-year-old  brown  trout  from  Caledonia 
in  races  22  and  23;  76  older  brown  trout;  and  700  to  750  brook  trout  of  varying  size 
and  age.  During  the  course  of  the  summer  the  rainbow  trout  retained  their  relative 
immunity  to  the  disease,  only  7  developing  visible  tumors  during  the  summer,  notwith- 
standing the  position  of  pond  13,  receiving  water  from  both  water  supplies,  all  of  it 
running  through  troughs  and  concrete  tanks  above,  in  which  the  disease  was  very  active. 


CARCINOMA   OF   THE   THYROID   IN   SALMONOID   FISHES.  439 

The  remainder  of  some  200  five-year-old  brown  trout  referred  to  in  the  summer  of  1908 
as  free  from  tumors  were  again  examined  closely  and  found  to  be  in  a  healthy  condi- 
tion, showing  no  visible  tumors. 

A  distinct  change,  however,  was  found  in  the  4,000  brown  trout  from  Caledonia, 
which  in  1 908  showed  no  evidences  of  visible  tumors.  This  lot  is  described  in  1 909  as 
consisting  of  about  3,000  fish,  now  2  years  old,  from  6  to  8  inches  in  length.  These  occu- 
pied cement  races  22  and  23.  Owing  to  insufficient  help,  it  was  not  possible  to  examine 
all  of  these  brown  trout.  However,  it  was  possible  to  determine  that  the  disease  in  this 
lot  was  now  well  established.  Forty-eight  died  or  were  picked  out  from  the  lot  and  found 
diseased.  This  does  not  represent  the  total  number  of  brown  trout  affected.  Between 
June  and  the  end  of  September,  among  the  fish  which  died  from  this  lot,  43  are  recorded 
as  having  been  examined  and  all  showed  visible  thyroid  tumors. 

The  brook  trout  of  the  hatchery  were  yearling  fish,  between  700  and  750  in  number, 
kept  in  races  10  and  n.  A  number  of  them  were  also  kept  in  race  14  and  in  the  large 
pond.  In  race  16,  wooden,  were  100  brook  trout  from  Cold  Spring  Harbor  hatchery. 
To  these  were  added  56  wild  brook  trout  from  the  Old  Forge  hatchery  later  in  the  sum- 
mer. By  the  middle  of  June  the  epidemic  among  the  brook  trout  was  at  its  height. 
These  fish  were  examined  a  number  of  times  and  some  of  the  affected  ones  were  put 
into  the  large  pond  and  others  into  the  small  pond  15.  On  June  24  the  fish  in  race  10 
were  examined  and  72  affected  fish  put  into  the  large  pond.  About  i  fish  in  every  3 
was  found  with  visible  tumors.  Race  n  contained  142  yearling  brook  trout.  Thirty 
affected  fish  were  found  in  race  n  and  placed  in  pond  15. 

The  remainder,  112  supposedly  healthy  fish,  were  removed  to  wooden  race  18. 
This  race  is  supplied  with  the  water  of  springs  C  and  F,  and  the  Cold  Spring  Harbor 
trout  kept  in  this  water  having  remained  free  from  the  disease  it  was  hoped  that  by 
changing  the  fish  from  race  1 1 ,  which  did  not  yet  show  evidences  of  visible  tumors,  they 
might  be  saved.  On  examining  these  fish  in  race  18  in  September,  107  of  the  112  were 
found  to  have  visible  tumors. 

During  the  summer  a  large  number  of  the  brook  trout  in  the  large  pond  died.  One 
hundred  and  five  of  these  were  found  to  have  visible  tumors.  Early  in  the  spring  the 
large  pond  which  in  September,  1907,  had  been  stocked  with  some  6,000  brook  trout 
fry  hatched  during  that  season  and  in  which  during  the  summer  of  1908  a  few  dead 
yearling  fish  were  found  with  visible  tumors,  was  again  cleaned,  the  fish  being  tempo- 
rarily transferred  during  this  time.  Some  200  of  these  brook  trout,  now  2  years  old, 
were  estimated  to  have  escaped  with  the  overflow  into  the  brook.  This  stream  was 
protected  by  a  screen  at  the  lower  end  of  the  hatchery  and  such  fish  as  escaped 
remained  in  the  brook  during  the  summer,  here  receiving  no  artificial  feeding  during 
this  time  and  enjoying  conditions  of  freedom  so  far  as  ample  space  and  lack  of  crowding 
were  concerned.  That  a  large  proportion  of  these  fish  were  affected  with  visible  tumors 
was  shown  by  the  fact  that  during  the  course  of  the  summer  105  died  of  the  lot  trans- 
ferred to  the  big  pond,  all  showing  visible  tumors,  and  to  determine  to  what  degree  they 
might  have  recovered  under  the  new  conditions  an  examination  was  made  on  Sept  em- 


44-O  BULLETIN   OF  THE  BUREAU  OF  FISHERIES. 

ber  ii.  The  stream  was  therefore  seined  and  48  fish  were  caught  and  examined.  Of 
these  3 1  were  found  to  have  visible  tumors,  many  of  large  size. 

Pond  15  had  been  the  receptacle  for  affected  fish  taken  from  the  different  troughs, 
tanks,  and  ponds.  There  were  approximately  450  fish  in  this  pond;  164  of  these  are 
recorded  as  dying  during  the  course  of  the  summer.  At  the  end  of  September  the 
remainder,  all  of  which  still  had  visible  tumors,  were  killed;  the  record  states  276  in  all. 

The  conditions  for  observation  at  the  Bath  hatchery  during  the  summer  of  1909  were 
unfavorable  owing  to  lack  of  records  as  to  the  origin  of  many  lots  of  fish,  to  inadequate 
help,  preventing  frequent  examination  of  the  various  lots,  and  to  frequent  changes  of  the 
various  lots  from  pond  to  pond,  due  to  the  exigencies  of  fish  culture.  The  most  important 
observations  made  were  the  marked  degree  to  which  the  water  of  the  big  pond  and  the 
tanks  it  supplied  were  involved  in  the  epidemic;  the  striking  evidences  of  immunity  in 
the  adult  rainbow  and  brown  trout  from  the  Caledonia  hatchery;  the  fact  that  the 
yearling  brook  trout  exposed  to  the  disease  in  pond  1 1  continued  to  develop  it  rapidly 
although  transferred  to  trough  18,  in  which  nevertheless  the  Cold  Spring  Harbor  yearling 
brook  trout  in  trough  16,  which  was  supplied  by  the  same  source,  springs  C  and  F, 
remained  free  from  the  disease  during  tne  summer;  and  the  lack  of  evidence  of  spon- 
taneous recovery  in  the  2-year-old  brook  trout  living  under  conditions  of  partial  freedom 
without  artificial  feeding  during  the  summer  in  the  brook;  the  high  incidence  of  the 
disease  in  the  large  pond,  A,  where  the  flow  of  water  and  proportionately  great  area 
of  the  pond  produced  conditions  much  more  favorable  from  this  standpoint  than  are 
usual  under  conditions  of  domestication;  and  the  rapidity  of  involvement  of  the  fish 
by  the  disease  and  the  great  number  affected. 

As  the  main  activities  of  this  research  were,  in  1909,  transferred  to  the  Craig  Brook 
station  in  Maine,  no  further  observations  were  made  at  the  Bath  hatchery  during  1910 
and  1911,  but  in  the  middle  of  October,  1912,  for  the  purpose  of  determining  what  the 
condition  of  this  hatchery  might  then  be,  an  inspection,  covering  one  day,  was  made. 
No  essential  changes  have  been  made  in  the  water  supply  or  other  arrangements  of 
the  hatchery  other  than  those  already  described.  The  hatchery  now  carries  a  stock 
of  about  3,000  brook  trout  hatched  in  the  spring  of  1911.  With  the  idea  that  fish 
hatched  from  the  eggs  of  wild  fish  might  prove  more  resistant  to  the  unfavorable  con- 
ditions in  this  hatchery,  eggs  were  obtained  from  the  Ontario  Fish  and  Game  Commis- 
sion in  Canada.  Approximately  1,500  fish  were  hatched  from  these  eggs  and  main- 
tained in  a  separate  trough.  The  remaining  1,500  fish  were  hatched  from  eggs  obtained 
from  a  private  hatchery  in  Massachusetts,  and  were  also  kept  in  a  separate  pond.  Both 
these  lots  of  fish  showed  well-developed  examples  of  the  disease  ranging  from  the  first 
evidence  of  red  floor  to  protruding  tumors  of  7  to  10  millimeters.  Of  the  1,500  fish 
hatched  from  the  wild-fish  eggs,  some  200  were  examined,  9  of  which  were  visibly  affected, 
and  200  examined  from  the  lot  of  1,500  hatched  from  the  eggs  from  the  Massachusetts 
hatchery  showed  12  diseased  fish.  From  this  inspection  it  is  evident  that  the  disease 
is  still  endemic  at  the  Bath  hatchery. 


CARCINOMA   OF  THE  THYROID   IN   SALMONOID   FISHES.  441 

HYBRIDIZATION. 

Hybrids  of  the  brook  trout  with  the  American  saibling  (Sunapee  trout)  and  with 
the  landlocked  salmon  do  not  differ  materially  from  the  pure  species  in  reaction  to 
thyroid  disease.  Lot  2017,  for  instance  (female  brook  and  male  landlocked  salmon), 
as  yearlings  showed  no  visible  process,  and  experienced  very  little  involvement  during 
four  years.  Lots  2036,  2037,  and  2038  (brook  plus  saibling)  were  little  affected  as 
yearlings,  but  considerably  at  three  years.  The  appearance  and  character  of  the  growth 
is  substantially  the  same  as  in  the  brook  trout.  These  crosses,  within  the  genus  Salve- 
linns  and  the  closely  related  Salvelinus  plus  Salmo,  are  more  or  less  successful,  and 
the  fish  resulting  are  hardy,  and  grow  to  maturity  and  reproduce. 

The  hybrids  of  the  Pacific  salmon,  though  all  contained  in  the  same  genus  (Onco- 
rhynchus) ,  are  greatly  inferior  in  vigor  to  their  constituent  species,  and  probably  could 
not  maintain  themselves.  They  do  not  do  well  under  fish-cultural  conditions,  are  not 
hardy,  and  easily  succumb  to  unfavorable  conditions.  Hybrids  of  the  silver  and  hump- 
back salmon  are  subject  from  the  embryo  to  deformity  of  the  spinal  column  in  the 
region  of  the  caudal  peduncle.  They  are  readily  susceptible  to  thyroid  disease.  One 
of  these  hybrid  lots  showed  as  yearlings  the  highest  incidence  of  visible  tumors  yet 
observed  in  any  large  homogeneous  brood  of  fish  (p.  67).  One  lot,  however  (silver 
plus  humpback,  igSSA),  consisted  at  the  first  examination  of  but  17  fish,  all  of  which 
were  tumored;  and  all  the  Pacific  hybrids  showed  a  high  percentage  of  tumors.  The 
general  gross  appearance  of  these  growths  is  markedly  different  from  that  of  the  trout 
tumors.  The  hybrid  tumors  have  a  marked  symmetry,  most  apparent  on  the  floor  of 
the  mouth.  Here  the  growth  as  it  vegetates  into  the  mouth  usually  occupies  the  median 
bridge,  and  spreads  equally  over  the  arches  so  that  the  right  and  left  halves  of  the 
tumor  are  alike,  and  a  distinct  and  sometimes  almost  perfect  bilateral  symmetry  appears. 
The  surface  of  the  growth  is  unusually  smooth.  The  benign  impression  which  results 
is  belied  by  the  structure,  which  in  these  growths  in  hybrid  salmon  is  among  the  most 
malignant  of  the  thyroid  tumors  in  fishes.  Likewise  the  cachexia  observed  among 
tumor  fishes  is  most  extreme  in  these  fish.  (Fig.  4a). 

CLINICAL  COURSE. 
MORBIDITY   AND    MORTALITY. 

There  is  no  very  definite  symptom  picture  among  the  affected  fishes.  The  disease 
usually  runs  a  slow  chronic  course.  The  earliest  external  evidences  may  doubtless 
occur  in  very  young  fish  only  a  few  months  old,  but  rarely  do  fish  of  this  age  show  any 
outward  signs  of  disease.  The  beginning  of  the  process  is  without  clinical  symptoms 
until  the  red  floor  or  an  evident  tumor  appears.  The  earliest  gross  tumor  we  have  seen 
is  in  a  brook  trout  about  5  months  old.  (Fig.  72.)  Not  many  tumors  are  seen  until  the 
fish  reach  the  yearling  stage,  when  the  growth  is  usually  still  small  and  not  causing  much 
interference.  In  certain  hybrid  salmon,  however,  and  occasionally  in  brook  trout,  the 
growths  in  yearling  fish  have  already  reached  a  relatively  great  size,  sometimes  almost 
their  maximum.  These  hybrids  die  rapidlv  and  do  not  grow  to  maturity.  In  brook 
8207°— 14 6 


442  BULLETIN  OF  THE  BUREAU  OF  FISHERIES. 

and  other  pure  trout  species  the  tumors  grow  progressively  with  the  growth  of  the  fish 
to  maturity.  At  the  spawning  season  gravid  fish  are  often  thrown  out  and  destroyed 
on  account  of  the  presence  of  large  thyroid  tumors,  and  doubtless  eggs  from  such  fish 
not  infrequently  find  their  way  into  the  hatchery.  As  far  as  we  know  they  may  be  fer- 
tilized and  hatched  like  the  eggs  of  other  trout. 

Only  the  larger  tumors  are  evident  to  a  casual  inspection  of  the  fish.  To  determine 
whether  a  fish  has  a  thyroid  tumor  it  is  necessary  to  examine  the  thyroid  region  from  all 
sides  after  spreading  wide  the  gills  and  opening  the  mouth.  A  considerable  proportion 
of  the  trout  in  fish-cultural  ponds  may  have  developed  visible  tumors  without  the  knowl- 
edge of  the  fish  culturist.  By  such  an  examination  31  per  cent  of  the  2-year-old  brook 
trout  at  one  hatchery  were  found  to  have  visible  thyroid  tumors,  while  33  per  cent 
showed  the  red  floor  indicative  of  an  earlier  stage  of  thyroid  disease. 

Thus  64  per  cent  were  visibly  affected,  although  the  fish  culturist  knew  of  the  exist- 
ence of  this  disease  only  from  having  occasionally  seen  a  dead  trout  with  a  swollen  gill 
region. 

The  first  obvious  effect  of  the  tumor  is  the  mechanical  interference  with  breathing 
and  eating  as  the  tumor  grows  larger.  By  filling  the  mouth  it  obstructs  the  passage  of 
food,  and  by  its  growth  downward  and  outward  it  spreads  the  gill  arches,  limits  their 
natural  movement,  and  pinches  off  the  vessels  until  in  portions  the  circulation  is  stopped. 
Large  tumors  often  show  across  their  surface  a  pale  atrophied  series  of  nonfunctional  gill 
filaments.  Yet  the  fish  succeeds  in  breathing  and  eating  in  spite  of  a  surprising  degree 
of  interference. 

Tumored  trout,  like  healthy  normal  trout,  ordinarily  have  the  blood  sterile  to  com- 
mon culture  media.  This  is  shown  by  negative  results  from  numbers  of  attempts  to 
obtain  cultures  from  the  heart  blood  of  freshly  killed  trout  with  tumors,  and  also  from 
tumor  trout  dead  of  disease.  That  tumor  trout  are  more  subject  to  terminal  infection 
than  other  trout  is  to  be  expected  and  is  probably  the  case,  though  some  meager  observa- 
tions made  by  us  at  a  State  hatchery  tend  rather  to  support  the  contrary  view.  Ter- 
minal blood  infection  in  the  living  as  well  as  the  dead  trout  has,  however,  been  observed, 
and  of  course  the  tumors  are  frequently  infected.  That  tumor  trout  frequently  die 
without  showing  a  general  infection,  or  evidence  of  intercurrent  disease,  indicates  that 
the  thyroid  process  itself  is  fatal  in  a  certain  proportion  of  cases.  This  intrinsic  death 
rate  is  probably  low,  but  can  not  easily  be  separated  from  the  rate  of  mortality  among 
tumor  fish  due  to  all  causes.  * 

Hybridization  seems  greatly  to  increase  the  susceptibility  of  the  salmonoids  to  the 
incidence  of  tumors  and  to  its  effect  on  their  bodily  economy.  In  some  of  these  the 
anemia  is  readily  recognizable  by  mere  inspection,  and  is  so  extreme  in  some  individuals 
that  the  blood  scarcely  appears  red.  A  case  in  point  is  the  lot  (no.  1994)  of  yearling 
salmon  (Oncorhynchus)  hybrids  of  the  female  blueback  with  the  male  humpback.  In 
April  they  numbered  1,043,  °f  which  16.7  per  cent  had  visible  tumors.  By  the  following 
August  they  had  suffered  a  loss  of  57  per  cent.  Of  the  594  remaining  92.5  per  cent 
had  visible  tumors.  These  showed  distinct  emaciation,  many  of  them  to  an  extreme 


CARCINOMA   OP  THE  THYROID  IN   SALMONOID   FISHES.  443 

degree,  with  the  accompanying  anemia  referred  to  above.  They  were  constantly  suc- 
cumbing to  the  disease,  and  the  slightest  handling,  as  during  the  manipulations  incident 
to  transportation,  greatly  increased  the  death  rate.  Before  the  following  summer  all 
were  dead.  The  reaction  of  the  disease  in  hybrids  does  not  afford  a  typical  clinical 
picture  and  is  not  a  criterion  from  which  to  infer  its  virulence  or  its  analogies  with  other 
disease  processes.  Most  hybrids  are  not  successful  fish-culturally,  and  the  salmon  hybrids 
referred  to  are  especially  defective  and  lacking  in  vigor. 

Restricting  morbidity  to  those  showing  macroscopic  evidence  of  disease,  such  as 
red  floors  or  visible  tumors,  the  morbidity  rate  is  widely  variant  among  the  various 
species  and  hybrids,  and  under  the  various  conditions  of  age  and  surroundings.  Our 
observations  show,  for  brook  trout  yearlings,  a  rate  from  a  minimal  one-half  of  i  per 
cent  to  28  per  cent;  for  2-year-olds,  20  per  cent  to  65  per  cent;  and  for  older  fish  from  5 
to  91  per  cent.  Considering  visible  tumors  only,  there  appears  one-half  of  i  per  cent 
to  7  per  cent  for  yearlings,  3  per  cent  to  38  per  cent  for  2 -year-olds,  and  i  per  cent  to 
34  per  cent  for  older  fish.  Landlocked  salmon  have  shown  visible  evidence  of  disease  in 
from  2  per  cent  to  7  per  cent  of  yearlings,  and  5  per  cent  to  37  per  cent  of  older  fish. 
With  rainbow  trout  our  experience  is  very  limited,  and  we  have  not  seen  more  than  6 
per  cent  of  adults  affected. 

Hybrids  of  the  brook  trout  and  saibling  react  much  like  the  brook  trout,  but  hybrids 
of  the  brook  trout  and  landlocked  salmon  seem,  from  experience  with  one  lot  only 
(no.  2017),  to  have  a  considerable  degree  of  immunity,  showing  no  involvement  until 
the  second  year,  and  at  4  years  only  5  per  cent  were  affected.  The  salmon  hybrids  of  the 
genus  Oncorhynchus  usually  show  extreme  susceptibility. 

On  the  other  hand,  the  same  hybrid  with  the  sexes  reversed  (lot  1995,  male  blueback 
and  female  humpback),  was  much  less  susceptible.  It  was  held  at  first  under  the  same 
conditions,  in  trough  99,  and  consisted  in  April  of  312  yearling  fish,  only  1.2  per  cent 
bearing  tumors.  In  the  following  August  there  were  146  fish  left,  of  which  5.5  per  cent 
had  tumors.  The  clean  fish  were  then  transferred  to  pond  4.  At  2  years  of  age  there 
were  77  fish  left,  of  which  13  per  cent  were  affected  and  9  per  cent  had  visible  tumors. 
At  3  years  of  age  27  fish  were  left,  and  of  these  37  per  cent  showed  red  floors  without 
any  visible  tumors. 

The  direct  and  indirect  mortality  rates  can  not  be  stated  numerically.  The  process 
presumably  does  not  kill,  whether  directly  or  indirectly,  save  in  the  later  stages  when 
the  tumor  is  visible,  and  the  only  available  data  on  the  loss  among  fish  in  any  stage  of 
thyroid  disease  is  so  complicated  with  losses  from  other  causes — even  causes  having 
nothing  to  do  with  disease,  that  any  accurate  statement  is  impossible.  The  mortality 
rate  is  to  all  appearances  not  uniform,  but  varies  from  a  slow  fish-culturally  unimportant 
loss  to  occasional  epidemic  virulence,  as  in  the  active  progress  of  the  disease  and  rapid 
loss  of  fish  at  the  State  hatchery  at  Bath,  N.  Y.  Ordinarily  and  in  the  common  exhibi- 
tion of  the  disease  the  death  rate  may  be  said  to  be  low. 

In  the  many  studies  of  the  distribution  of  goiter  among  human  beings  none  is  so 
striking  or  apparently  so  directly  comparable  to  the  conditions  found  in  the  study  of 
the  disease  in  fish  hatcheries,  as  the  observations  of  McCarrison,  1906,  of  endemic  goiter 


444  BULLETIN  OF  THE   BUREAU  OF  FISHERIES. 

in  the  Chitral  and  Gilgit  Valleys  of  north  India.  McCarrison  had  the  opportunity  of 
studying  endemic  conditions  among  the  inhabitants  of  the  small  villages  of  this  remote 
region.  His  observations  are  of  particular  value  because  the  people  in  these  small 
States  of  northern  India  are  remote  from  commerce,  communication  is  extremely  limited, 
many  of  the  communities  are  shut  off  from  communication  even  with  their  neighbors, 
and  the  conditions  which  he  describes  represent  the  development  of  the  disease  under 
almost  fixed  conditions.  In  the  Chitral  Valley  he  describes  a  series  of  villages  lying 
along  the  left  bank  of  the  Chitral  River,  each  village  deriving  its  water  supply  from 
the  narrow  mountainous  valleys  at  the  openings  in  which  the  villages  lie. 

The  water  supply  is  in  all  cases  derived  from  the  melting  of  the  snows  on  the  hills  above.  It  comes 
from  the  nullah  at  the  mouth  of  which  the  village  stands,  and  is  the  only  supply  of  that  village.  As  a 
rule  the  water  from  the  melting  snows  runs  down  the  nullah  as  a  turbulent  mountain  stream,  taking 
up  what  matter  it  may  on  its  way  either  in  solution  or  suspension;  in  other  cases  it  percolates  into  the 
soil  and  appears  lower  down  in  the  form  of  a  spring,  as  in  the  case  of  Awi.  In  the  summer  months  the 
water  is  invariably  gray  from  the  presence  of  fine  sediment.  There  are  no  real  glaciers  in  the  district 
under  observation ;  the  water  is  snow  water  rather  than  glacier  water.  There  are  no  wells  in  the  village , 
and,  owing  to  the  slope  of  the  ground  and  the  nature  of  the  soil,  water  does  not  and  can  not  stagnate. 

The  incidence  of  goiter  in  these  villages  varies  from  10  per  cent  to  58  per  cent  and 
appears  to  be  dependent  upon  the  local  conditions  of  the  village  and  its  water  supply. 
As  compared  with  the  appearance  of  the  disease  in  the  villages  of  Chitral,  McCarrison 
had  observed  in  Gilgit  a  remarkable  increase  of  the  incidence  of  goiter  in  a  series  of 
villages  scattered  along  an  irrigation  ditch  where  the  incidence  of  the  disease  increases 
from  above  downward. 

Gilgit  lies  between  the  parallels  of  latitude  35°  and  37°  and  meridians  of  longitude  74°  and  75°. 
It  is  only,  however,  with  Gilgit  proper,  the  capital  of  the  district,  and  not  with  the  whole  of  this  district 
that  these  observations  deal.  Gilgit  is  situated  on  an  alluvial  fan  on  the  right  bank  of  the  Gilgit  River, 
a  tributary  of  the  Indus.  This  fan  is  roughly  10  square  miles  in  extent  and  has  a  gentle  slope  from  its 
apex,  in  the  nullah  from  which  it  derives  its  water  supply,  to  the  river.  On  this  extensive  fan  eight 
villages  are  situated;  collectively  these  are  known  as  Gilgit.  The  remarks  which  I  have  made  as  to 
the  climate  and  people  of  Chitral  apply  equally  to  Gilgit.  The  valley  runs  east  and  west.  The  height 
of  the  fan  above  sea  level  is  5,105  feet.  Appended  is  a  rough  diagrammatic  sketch  which  shows  clearly 
the  water  supply  of  the  different  villages  of  the  Gilgit  fan. 

The  water  comes  from  a  single  source  and  is  conveyed  to  the  different  villages  in  open  kuls  or  chan- 
nels. From  the  diagram  it  will  be  observed  that  there  are  two  main  channels,  an  upper  11  and  a  lower 
(i).  The  upper  channel  has  no  villages  on  its  banks  till  it  joins  the  lower  kul,  at  the  village  of  Majin- 
pharri,  marked  (3).  All  these  seven  villages  are  situated  on  the  banks  of  this  lower  kul  or  are  supplied 
by  lesser  channels  branching  from  it.  Each  village  in  this  way  receives  the  drainings"  of  the  village 
or  villages  above  it,  till  at  the  last  village,  Kashrote,  the  drinking  water  has  been  polluted  by  the  six 
villages  above. 

The  water  in  these  open  channels  not  only  supplies  the  inhabitants  with  drinking  water,  but  it 
irrigates  their  extensive  crops,  serves  as  an  open  sewer,  is  used  for  the  cleansing  of  their  bodies,  house- 
hold utensils,  and  wearing  apparel.  It  can  readily  be  imagined,  therefore,  that  considerable  organic 
impurities  find  their  way  down  to  the  lower  villages;  yet,  being  fed  as  these  channels  are  by  a  purer 
supply,  little  organic  impurity  can  be  detected  by  qualitative  tests. 

The  water  is,  during  the  winter  months,  at  its  source  clear  and  sparkling,  but  at  the  village  of 
Kashrote  (see  diagrammatic  sketch  of  water  supply  and  plate  Gilgit  Valley,  western  end)  invariably 
gray  from  the  presence  of  fine  sediment  and  impurities  from  the  villages  and  lands  irrigated  by  it. 
During  the  summer  months  when  the  snows  are  melting  it  is,  of  course,  much  worse. 


CARCINOMA  OF  THE  THYROID  IN  SALMONOID  FISHES. 


445 


If  the  sketch  of  the  Gilgit  water  supply  is  referred  to  it  will  be  observed  that  the  Barmis  spring 
joins  the  supply  already  described  at  3,  Majinpharri.  This  spring  does  not  produce  goiter;  it  is  the 
supply  of  all  the  European  residents  and  their  servants;  there  is  also  a  small  village  on  its  banks,  among 
the  inhabitants  of  which  there  is  no  single  case  of  the  disease.  It  is  a  very  pure  water,  springs  from 


5. 


FIG.  83.— Diagrammatic  sketch  showing  water  supply  of  the  villages  of  Gilgit  fan,  India.    After  McCarrison. 

among  rocks,  and  I  have  been  unable  to  trace  any  case  of  the  disease  due  to  the  drinking  of  its  water. 
This  is  a  point  of  very  considerable  importance,  showing  as  it  does  that  the  other  water  supply  is  the 
vehicle  by  means  of  which  goiter  is  produced  in  the  inhabitants  of  Gilgit.  The  analysis  of  this  water 
of  Barmis  will  be  found  in  the  table  of  analyses  of  Gilgit  waters  (table  in). 


446 


BULLETIN   OF  THE   BUREAU  OF  FISHERIES. 


In  considering  the  prevalence  of  goiter  in  the  villages  of  Gilgit  the  villages  are  dealt  with  in  order, 
from  that  highest  on  the  water  supply  to  that  lowest  (see  sketch  of  water  supply).  The  figures  are  given 
in  the  following  table: 


i 
Village. 

Popula- 
tion. 

Houses. 

Infected  houses. 

Persons 
infected 
in 
infected 
houses. 

Total 
popula- 
tion 
goitrous. 

z.  Basin  

Number. 

93 

38s 
181 
718 
229 
458 
128 

Number. 
15 
66 
30 
108 
33 
63 
24 

Number. 
9 
42 
20 
68 
23 
5» 

21 

Per  cent. 
60.  o 
63-6 
66.6 

63-  2 

71-5 
82.S 
87.0 

Per  cent. 
ai.  a 
28.3 
3°-3 

24.  2 
3O.O 
30.0 
36.0 

Per  cent. 
u.8 

20.0 

1  8.  8 

20.0 
26.9 
24-  S 

45-6 

2.  Umpharis  

3.  TD^Tiy^l    ,  

4.  Majuiipharri  

5,6.  Kyk  

g.  Kashrote  

It  is  quite  clear  that  McCarrison  has  observed  conditions  which  are  remarkably 
comparable  to  the  conditions  found  in  the  Craig  Brook  hatchery  where  we  originally 
found  the  increase  of  the  disease  from  above  downward  in  the  ponds,  with  absence  of 
the  disease  in  the  two  uppermost  ponds  fed  with  individual  spring  water  supply 
(fig.  78,  p.  429) ;  also  to  the  conditions  which  we  have  described  at  Cold  Spring  Harbor. 

The  age  incidence  of  visible  manifestations  of  this  disease  including  both  red  floors 
and  tumors  affords  material  for  a  comparison  of  the  incidence  of  the  disease  as  we  have 
observed  it  in  fish  and  that  of  goiter  in  the  inhabitants  of  the  villages  of  Chitral  and 
Gilgit  Valleys,  as  recorded  by  McCarrison,  as  well  as  that  of  goiter  in  school  children 
as  given  by  Schittenhelm  and  Weichardt.  McCarrison  examined  646  inhabitants  of 
the  villages  of  Chitral,  of  which  277  were  children  under  15,  and  369  adults.  At  5 
years  of  age  male  children  showed  40  per  cent,  female  22  per  cent.  The  incidence  of 
the  disease  rises  rapidly  to  15  years  where  the  males'  showed  74  per  cent,  females  59^ 
per  cent.  From  this  age  it  rapidly  fell  in  both  cases  so  that  at  25  years  of  age  males 
showed  40  per  cent,  females  24  per  cent.  From  25  years  on,  the  incidence  in  females 
again  rose,  until  the  age  of  45  when  62  per  cent  were  affected,  the  males  having  steadily 
fallen  to  23  per  cent  at  the  same  age  period.  In  Gilgit  the  total  population  examined 
was  1,533,  °f  which  705  were  children  under  15  years  and  828  adults.  The  incidence 
for  males  and  females  varies  slightly.  At  5  years  of  age  2  per  cent  of  the  males  and 
at  1 5  years  of  age  1 6  per  cent  of  the  males  and  20  per  cent  of  the  females  were  affected. 
In  this  locality  the  incidence  steadily  rose  to  40  years  of  age  when  45  percent  of  the 
males  and  36  per  cent  of  the  females  were  affected.  McCarrison  states  that  in  Chitral 
23  per  cent  of  children  under  i  year  of  age  who  are  still  being  suckled  suffer  from  this 
disease  in  the  village  of  Awi,  and  in  another  village,  Miragram,  the  percentage  figure 
was  even  higher  than  this,  reaching  61.5  per  cent.  The  mothers  had  in  all  cases  been 
the  subject  of  the  disease  and  frequently  the  fathers  also.  What  proportion  of  these 
cases  were  congenital  and  what  acquired  he  was  unable  to  determine. 

Schittenhelm  and  Weichardt  state  that  in  a  typical  goitrous  community  in  Bavaria 
the  incidence  of  goiter  as  expressed  by  demonstrable  enlargement  of  the  thyroid  is, 
from  2  to  6  years  of  age,  42  per  cent;  6  to  9,  72.4  per  cent;  9  to  13,  89.6  per  cent;  and 


CARCINOMA  OF  THE  THYROID  IN  SALMONOID  FISHES.  447 

that  for  recruits  who  have  reached  the  age  for  military  service  for  the  district,  9.22 
per  cent.  From  this  it  would  appear  that  there  is  a  steady  increase  of  goiter  in  school 
children  up  to  the  age  of  puberty,  with  a  marked  decrease  between  that  age  and  20. 

Our  tables  show  that  for  brook  trout  yearling  fish  the  maximum  is  28  per  cent, 
.or  2-year-olds  65  per  cent,  and  for  fish  older  than  2  years  91  per  cent.  It  may  be 
stated  for  brook  trout  in  captivity  that  a  large  proportion  of  them  at  least  have  acquired 
their  reproductive  faculties  in  the  second  year  and  that  their  full  reproductive  faculties 
are  certainly  acquired  by  the  third  season.  It  thus  appears  from  our  figures  that  fish 
exhibit  a  very  high,  probably  the  highest,  incidence  in  the  period  from  2  to  5  years, 
which  in  the  life  of  a  fish  carries  it  well  beyond  the  comparable  period  in  human  beings. 
We  have  frequently  met  with  instances  of  actively  growing  tumors  in  the  oldest  fish 
under  observation  and  the  large  tumors  in  old  fish  have  never  presented  an  appearance 
comparable  to  colloid  goiter.  So  far  as  this  comparison  is  admissible  it  would  indicate 
that  the  process  in  the  fish  in  its  age  incidence  is  more  in  accord  with  McCarrison's 
observations  than  the  Bavarian  statistics  just  quoted.  Both  McCarrison's  statistics 
for  man  in  Chitral  and  Gilgit  and  our  own  for  fish  reach  well  into  the  period  of  increasing 
incidence  of  neoplasms  in  mammals. 

HEMOGLOBIN    ESTIMATIONS. 

In  the  autumn  of  1902,  before  thyroid  carcinoma  in  fishes  had  attracted  attention 
in  this  country,  one  of  us  observed,  incidental  to  work  upon  bacterial  infection  in  trout, 
an  anemic  condition  among  a  certain  lot  of  brook  trout  at  a  State  hatchery  at  Paris, 
Mich.  These  fish  were  i^  years  old  and  were  part  of  a  lot  of  several  hundred  which 
had  been  sorted  and  segregated  from  the  general  hatchery  stock  on  account  of  their 
undersized  and  stunted  condition.  Except  for  their  small  size  this  lot  was  in  fair 
condition  and  most  of  them  would  have  spawned  for  the  first  time  some  weeks  subse- 
quent to  these  observations.  Of  this  selected  lot  the  percentage  having  tumors  was 
not  determined  but  there  were  more  normal  healthy  fish  than  those  bearing  tumors. 
Even  the  tumor  fish  with  anemia  showed  no  particular  emaciation  or  falling  off  in 
condition. 

Nine  apparently  healthy  fish  without  tumors  were  taken  at  random  from  this  lot 
and  hemoglobin  readings  obtained.  Nineteen  tumor  fish  from  the  same  lot  then  had 
their  hemoglobin  estimated  in  the  same  way.  The  range  of  the  former  was  from  30  to 
43,  of  the  latter  from  almost  nothing  1047,  the  averages  being  37.5  and  21.6,  respectively. 
The  readings  were  made  with  a  Dare  hemoglobinometer;  those  recorded  as  8  are  arbi- 
trarily overstated,  the  samples  scarcely  showing  red  and  registering  much  below  the 
lowest  scale  reading.  The  fish  showing  the  highest  reading  (47)  had  only  a  very  small 
tumor,  in  the  jugular  pit.  The  largest  fish  of  the  series  (first  of  the  table)  showed  one 
of  the  lowest  readings,  and  had  marked  blood  changes.  The  tumors  were  not  measured 
or  accurately  compared,  but  the  larger  usually  gave  the  lowest  readings.  A  marked 
poikilocytosis  accompanied  a  low  blood  count  for  red  cells.  The  normal  red  cells 
numbered  256,000  per  cubic  millimeter,  or  416,000  including  the  atypical  reds  of  extra- 
ordinarily small  size.  The  red  cells  of  normal  brook  trout  blood  number  about  i  ,000,000 
per  cubic  millimeter. 


448 


BULLETIN   OF  THE   BUREAU   OF   FISHERIES. 


While  tumor  fish  not  infrequently  have  blood  infections,  plates  made  from  the  heart 
blood  of  several  of  these  tumor  fish  remained  sterile,  save  in  one  case.  The  hemoglobin 
readings  and  other  data  for  each  individual  are  given  in  the  following  table  : 

TABLE  VI.— HEMOGLOBIN   ESTIMATIONS  ON  THE   BLOOD  OF  TROUT  AT  THE  STATE  HATCHERY  AT 

PARIS,  MICH.,  IN  OCTOBER,  1902. 


Sex. 

Length. 

Hemo- 
globin, o 

Sex. 

Length. 

Hemo- 
globin. 6 

CLEAN  FISH. 
Mate 

Centi- 
meter . 
5 

TUMOR  FISH. 
Male  

Centi- 
meters. 
20 

Do 

38 

Do  

16 

36 

Do  

16 

Do 

Do  

16 

Do 

Do  

16 

Do..        .                   

38 

Do  

15 

28 

Do 

Female                

16 

g 

Do      

18 

8 

Do  

Do  

Do  

10 

i 
i 

z 
i 
i 
i 
i 

19 
ii 
27 
8 
8 
18 
8 
29 

Average  37.5. 


6  Average  21.6. 


SPONTANEOUS   RECOVERY. 


In  the  microscopic  examination  of  sections  of  carcinoma  of  the  thyroid  at  Craig 
Brook  station  during  the  summer  of  1909,  we  occasionally  encountered  what  appeared 
to  us  to  be  evidences  of  regression  in  certain  tumors.  We  therefore  were  led  to  look 
for  evidences  of  spontaneous  recovery.  To  determine  whether  a  change  to  more  favor- 
able conditions  on  the  part  of  the  fish  would  increase  the  number  of  spontaneous  recov- 
eries, in  the  autumn  of  1909,  119  fish  with  visible  tumors,  mostly  of  large  size,  were 
selected  from  a  lot  of  landlocked  salmon  (lot  1950),  and  placed  in  pond  i  at  Craig 
Brook  station.  During  the  winter  of  1909-10  two  yearling  brook  trout  with  small 
thyroid  tumors  visible  at  the  isthmus  were  held  without  food  in  a  glass  jar  in  the  cold 
with  occasional  changes  of  water.  One  died  after  a  few  weeks  with  the  tumor  still 
visible.  During  44  days  the  tumor  of  the  other  fish  disappeared  entirely,  leaving  the 
entire  thyroid  region  without  external  enlargement.  In  the  early  spring' of  1910  an 
examination  of  the  119  tumor-bearing  fish  in  pond  i  was  made  to  determine  to  what 
extent  spontaneous  recovery  might  have  affected  this  advanced  lot.  The  conditions 
in  the  pond  were  more  favorable  than  in  the  pond  below.  Here  the  fish  received  pure 
water  directly  from  a  spring,  had  access  to  natural  vegetation,  and  obtained  from  their 
surroundings  some  natural  food  while  they  were  fed  very  little  artificial  food.  Thus 
they  were  in  a  large  degree  removed  from  fish  culture.  During  a  year  the  loss  was 
67  per  cent  and  of  the  remaining  fish  only  56  per  cent  showed  visible  tumors. 


CARCINOMA   OF  THE   THYROID   IN   SAUMONOID   FISHES.  449 

Aside  from  the  actually  observed  subsidence  of  visible  tumors  under  some  abate- 
ment of  the  conditions  of  domestication,  trout  taken  at  random  from  fish-cultural  ponds, 
with  clean  thyroid  region,  show  the  usual  microscopic  picture  associated  with  thyroid 
known  to  have  recovered  from  tumor  formation.  The  wild  trout  used  in  feeding  experi- 
ments showed  numerous  examples  of  this  sort.  (Fig.  91-92.)  That  trout  can  recover 
under  apparently  the  same  conditions  under  which  they  acquire  the  disease,  and  under 
which  other  trout  are  showing  progressive  tumors,  seems  sufficiently  attested  by  our 
experience. 

Recognition  of  spontaneous  recovery  is  a  necessary  factor  in  studying  the  controls 
of  fish  treated  with  various  metals.  It  is  a  remarkable  fact  that  in  only  three  or  four 
instances  in  a  total  of  46  controls  did  we  find  spontaneous  recovery  under  the  conditions 
selected  for  these  experiments.  Regression  does  not  appear  to  occur  until  after  the  dis- 
ease has  continued  for  some  time.  The  best  evidence  of  regression  from  moderate  hyper- 
plasia  is  found  in  the  wild  Wisconsin  brook  trout  with  selected  feeding,  in  tanks  i  and  2 
containing  lots  2146  and  2147.  (See  table  vm,  p.  100.) 

In  this  experiment  at  the  end  of  one  year,  fish  fed  upon  raw  liver  and  raw  ox  heart 
showed  marked  hyperplasia,  whereas  those  fed  upon  various  other  types  of  food  showed 
no  evidence  of  hyperplasia.  At  the  end  of  two  years  the  only  lots  of  fish  remaining  free 
from  evidence  of  hyperplasia  were  those  fed  upon  natural  food  (i.  e.,  live  maggots,  fresh 
water  and  salt  water  mussels,  etc.),  whereas  those  which  had  from  the  beginning  been 
fed  upon  raw  liver  or  raw  ox  heart  in  the  various  experiments,  showed  a  few  individuals 
with  well-developed  visible  tumors  and  a  large  number  with  well-defined  evidences  of 
retrograding  hyperplasia.  A  microscopic  examination  of  various  fish  from  these  lots 
will  serve  to  characterize  the  changes  which  indicate  regression  of  the  earlier  stages  of 
the  disease.  See  2099,  2101,  2103,  2104,  on  pages  101  and  102. 

Summed  up,  these  changes  are  the  evidences  of  an  increased  amount  of  thyroid 
tissue  indicated  by  the  presence  of  follicles  in  regions  in  which  they  do  not  normally 
occur.  The  follicles  are  not  closely  packed  as  in  active  hyperplasia,  there  is  no  evidence 
of  hyperemia,  there  is  a  well-defined  stroma,  the  stroma  often  forming  trabeculae  between 
the  alveoli  as  wide  or  often  wider  than  the  diameter  of  the  follicles.  The  follicles  them- 
selves show  great  variety  in  size,  a  few  larger  ones  are  filled  with  stainable  colloid,  but 
the  majority  of  them  are  small,  of  irregular  shape  and  free  from  colloid  or  are  but  partly 
filled  with  poorly  stainable  colloid.  The  epithelium  is  flattened,  often  definitely  atrophic, 
the  protoplasm  greatly  reduced  in  amount,  so  that  the  cells  are  composed  for  the  great 
part  of  their  nuclei,  which  stain  homogeneously  and  deeply.  (Fig.  91.)  Frequently 
evidences  of  there  having  been  more  than  one  layer  of  epithelium  may  be  found.  The 
greatest  changes  are  in  the  peripheral  regions,  which  is  characteristic  of  the  regression 
of  all  neoplasms.  The  evidence  of  the  previous  branching  and  irregular  tubular  type 
of  proliferation,  which  characterizes  the  growing  tumor,  are  found  in  atrophic  struc- 
tures of  tubular  and  branching  shape,  sometimes  reduced  to  a  mere  cord  of  cells.  (See 
fig.  92.) 

From  a  survey  of  such  specimens  it  is  clear  that  an  actual  disappearance  of  thyroid 
tissue  must  have  taken  place.  In  the  earlier  stages  of  regression  from  large  tumors 


450  BULLETIN  Of  THE  BUREAU  OP   FISHERIES. 

evidences  of  extensive  hemorrhage  are  found,  a  characteristic  which  also  distinguishes 
regression  following  treatment  with  metals.  In  such  cases  organization  of  the  areas  of 
hemorrhage  by  connective  tissue  appears.  (Fig.  101.)  In  the  earlier  stages  of  regression 
the  periphery  of  the  tumor  will  frequently  show  evidences  of  round-celled  infiltration 
in  the  stroma.  The  scirrhous  appearance  of  advanced  tumors  which  have  undergone  re- 
gression is  distinctly  characteristic.  It  will  be  seen  that  these  changes  are  distinct  from 
the  changes  following  so-called  resolution  of  hyperplastic  thyroid  which  leads  to  the 
stage  of  colloid  goiter,  as  observed  in  the  Scotch  sea  trout,  where  the  terminal  stage  of 
simple  hyperplasia  is  the  large  follicles  filled  with  stainable  colloid,  lined  by  flattened 
epithelium.  (Fig.  22.)  The  changes  here  described  as  regressive  are  of  the  same  nature 
as  those  encountered  in  the  regression  of  transplanted  or  spontaneous  carcinoma  of  the 
breast  in  mice.  (Gaylord  and  Clowes,  1906.)  The  microscopic  picture  of  retrograding 
large  tumors  in  no  way  differs  from  the  changes  following  regression  by  treatment  with 
iodine,  arsenic,  or  mercury,  except  that  no  doubt  in  the  latter  instance  the  changes  pro- 
ceed more  rapidly  and  with  less  evidence  of  stroma  formation.  (Fig.  109.) 

IMMUNITY. 

Among  marine  species  it  has  been  remarked  that  the  chinook  salmon  held  at  the 
Craig  Brook  station  until  3  years  of  age  were  entirely  immune  to  visible  thyroid  growth. 
These  fish  were  nevertheless  in  poor  condition,  and  did  not  grow  and  thrive  normally. 
This  fish  is  anadromous,  and  under  natural  conditions  the  young,  being  hatched  in  fresh 
water,  soon  find  their  way  to  sea.  Notwithstanding  this,  they  may  survive  and  grow 
to  maturity  when  held  captive  in  fresh  water.  It  might  be  inferred  that  the  immunity 
which  resides  in  marine  species  of  salmonoids,  or  the  protection  which  the  sea  affords 
them — no  marine  species  having  been  found  in  the  sea  with  thyroid  enlargement — is 
transmitted  through  the  eggs  and  continued  during  a  prolonged  sojourn  in  fresh  water. 
But  the  humpback  salmon  is  likewise  a  Pacific  marine  species,  and  yearlings  of  this  kind 
produced  at  Craig  Brook  are  fine  examples  of  thyroid  tumors.  Of  319  fish  (lot  1986) 
about  i  year  old,  14  per  cent  bore  tumors  when  examined  in  April.  By  the  following 
August  only  79  fish  remained,  of  which  84.8  per  cent  had  tumors.  These  resembled  the 
tumors  of  the  Pacific  hybrid  salmon  and  showed  the  same  structural  evidence  of  malig- 
nancy. Wilkie  reported  (Gilruth,  1902)  a  thyroid  tumor  in  a  5-year-old  Atlantic  sal- 
mon in  fresh  water  in  the  ponds  of  the  Clinton  hatchery,  New  Zealand,  and  we  have 
seen  one  example  at  the  Craig  Brook  hatchery  in  Maine.  It  is  evident  that  marine 
species  may  develop  thyroid  carcinoma  while  resident  in  fresh  water. 

The  best  example  of  species  immunity  is  afforded  by  the  Scotch  sea  trout,  which  at 
Craig  Brook  is  almost  completely  immune  either  to  visible  or  microscopic  enlargement. 
One  doubtful  case  of  a  distinct  tumor  is  recorded  and  several  of  red  floors,  at  3,4,  and  5 
years  of  age.  Doubtless  trout  of  this  species  can  not  continue  indefinitely  without 
affection  under  the  conditions  which  produce  the  disease. 

While  the  Pacific  salmon  hybrids  all  show  a  high  susceptibility,  other  hybrids  and 
the  brook  trout  species  exhibit  various  degrees  of  susceptibility  and  immunity  to  tumor 
formation.  The  landlocked  salmon  is  about  as  susceptible  as  the  brook  trout,  but  lot 


CARCINOMA   OF  THE  THYROID  IN   SAI^MONOID   FISHES.  451 

1944  showed  no  visible  evidence  of  thyroid  disease  until  the  fourth  year,  though  living 
under  the  conditions  which  produced  the  disease.  Lot  2017,  hybrids  of  the  brook  trout 
and  landlocked  salmon,  when  it  consisted  of  1,553  yearling  fish,  showed  not  a  single  fish 
with  a  visible  process.  In  the  second  and  fourth  years  a  few  visible  growths  appeared. 
A  lot  (2133)  of  rainbow  trout,  which  develops  frequent  and  large  tumors  at  some  hatch- 
eries, were  held  two  years  at  the  Craig  Brook  station  without  acquiring  any  visible 
tumors  and  only  a  small  percentage  of  red  floors. 

As  previously  referred  to,  rainbow  trout  at  the  Caledonia  hatchery  in  New  York 
appeared  to  have  a  very  low  incidence  of  the  disease,  about  one-half  of  i  per  cent  of  the 
fish  each  year  showing  well-developed  tumors,  this  covering  a  period  of  approximately 
25  years.  As  stated,  no  fresh  blood  during  that  period  was  added  to  this  lot  of  fish. 
Tumor  fish  found  each  year  were  destroyed  and  a  probable  original  resistance  of  the  lot 
was  protected  and  perhaps  added  to  by  this  form  of  selection,  so  that,  as  we  have  pointed 
out,  in  the  epidemic  at  the  Bath  fish  hatchery  covering  a  period  of  two  years  these  fish 
remained  practically  immune,  only  i  or  2  fish  in  a  lot  of  75  adult  fish  being  found  with 
tumors  in  the  course  of  the  two-  years'  epidemic.  Exactly  the  same  state  of  affairs 
existed  in  a  lot  of  20,000  German  brown  trout  which  had  also  been  held  without  the 
addition  of  fresh  blood  at  the  Caledonia  hatchery.  These  were  represented  among 
others  by  some  200  of  their  offspring,  which  as  4  and  5  year  old  fish  went  through  the 
epidemic  without  a  single  tumor.  This  was  not  the  case  with  some  4,000  young  German 
brown  trout  which  were  sent  from  the  Caledonia  hatchery  to  the  Bath  hatchery  as 
young  fish,  and  which  toward  the  end  of  the  epidemic,  as  2-year-old  fish,  developed  a 
considerable  incidence  of  the  disease. 

That  the  rainbow  and  brown  trout  retained  so  *nany  years  at  the  Caledonia  hatchery 
really  possessed  a  definite  immunity  against  the  disease  is  shown  by  the  fact  that  during 
this  time  attempts  to  rear  brook  trout  to  adult  age  and  maintain  them  resulted  in  a  high 
incidence  of  thyroid  tumors  in  this  species.  That  a  given  lot  of  fish  from  one  hatch  may 
possess  at  a  certain  age  an  almost  complete  resistance  to  the  disease,  while  another  lot 
from  another  hatch  of  the  same  species  and  of  the  same  age,  kept  under  the  same  condi- 
tions, may  show  a  high  incidence  of  the  disease,  is  possibly  explainable  on  the  basis  of 
blood  relationship.  The  manner  in  which  spawn  and  eggs  are  taken  and  fertilized 
would  easily  bring  about  the  presence  in  any  given  lot  of  a  large  number  of  fish  with  the 
same  parents.  With  the  exception  possibly  of  the  hybrids,  some  of  the  lots  of  which 
were  small,  no  lot  of  fish  which  we  have  studied  could  possibly  be  entirely  of  the  same 
parentage;  but  as  a  large  number  of  individuals  in  each  lot  are  certainly  of  the  same 
parentage  it  is  explainable  that  the  high  degree  of  immunity  or  susceptibility  in  a  given 
lot  may  be  due  to  this  fact.  Such  a  supposition  is  in  accord  with  the  now  well-known 
facts  of  family  predisposition  in  both  goiter  and  cancer  in  human  beings. 

The  fish  offer  a  remarkable  opportunity  for  the  careful  study  of  this  phase  of 
immunity.  It  will  be  easily  possible  to  obtain  in  any  hatchery  in  which  the  disease 
is  endemic,  on  the  one  hand  from  parents  both  having  visible  tumors,  or,  on  the  other, 
from  parents  showing  distinct  immunity,  a  sufficient  number  of  eggs  to  hatch  several 
hundred  fish.  A  number  of  fish  could  be  reared  from  such  lots  sufficient  to  demon- 


452  BULLETIN  OF  THE   BUREAU  OF  FISHERIES. 

strate  clearly  in  a  few  generations  the  exact  importance  of  blood  relationship  to  sus- 
ceptibility and  immunity.  To  guard  against  possible  accidents  obviously  a  series  of 
such  experiments  should  be  carried  on  at  the  same  time  and  to  this  purpose  it  would 
be  necessary  to  devote  the  entire  activities  of  a  fish-cultural  station  for  a  period  of  years. 

The  importance  of  such  ah  investigation  to  the  question  of  immunity  in  goiter 
and  cancer  would  certainly  justify  such  an  undertaking,  aside  from  the  possibility  of 
practical  results  to  fish  culture.  Only  in  this  way  can  the  importance  of  inbreed- 
ing as  practiced  in  fish  culture  in  the  production  of  a  general  susceptibility  among 
domesticated  fish  to  this  disease  be  properly  determined.  It  is  a  common  assumption 
that  hatchery  fish  are  more  or  less  inbred.  We  have  emphasized  this  idea  in  our 
earlier  statements.  A  marked  susceptibility  of  at  least  one  lot  of  pure  marine  salmon 
species,  i.  e.,  the  humpback,  and  in  fact  the  occasional  occurrence  of  the  disease  in 
wild  fish,  indicate  that  inbreeding  as  such,  except  by  the  perpetuation  and  accentua- 
tion of  such  susceptibility,  may  not  be  considered  an  important  factor  and  the  facts 
developed  in  connection  with  the  rainbow  and  brown  trout  at  Caledonia  clearly  show- 
that  fish-cultural  inbreeding  may  finally  develop  a  markedly  resistant  strain. 

To  what  extent  spontaneous  recovery  from  the  disease  results  in  acquired  immunity 
is  not  easy  to  state.  There  are  many  facts  in  this  investigation  which  indicate  strongly 
that  recovered  fish  remain  immune  for  a  considerable  period  of  time  if  not  indefinitely. 
An  experiment  to  determine  definitely  this  question,  although  carried  out  with  too 
few  individuals,  failed  to  realize  the  development  of  visible  tumors  in  recovered  fish 
at  the  end  of  one  year,  although  placed  in  one  of  the  lowermost  ponds  where  the  inci- 
dence of  the  disease  continued  to  be  high. 

McCarrison  (1906),  in  his  study  of  endemic  goiter  in  the  Chitral  and  Gilgit  Valleys, 
gives  striking  examples  of  family  predisposition  to  goiter  and  refers  to  the  frequent 
occurrence  of  goiter  in  nursing  children  where  the  mother  has  the  disease.  Schittenhelm 
and  Weichardt  (1912),  in  their  recent  monograph  on  endemic  goiter  in  Bavaria,  state 
that  it  is  easy  to  trace  family  predisposition  to  goiter  and  append  family  trees  of  some 
1 3  families,  from  which  it  may  be  readily  seen  that  certain  families  show  a  remarkable 
incidence  of  the  disease,  which  is  especially  marked  in  children  where  one  or  both  parents, 
and  especially  when  both  parents  and  grandparents,  are  affected  by  goiter.  There 
are  several  experimental  studies  in  the  lower  animals  indicating  family  susceptibility 
to  cancer,  the  most  striking  being  the  breeding  experiments  of  Dr.  Maud  Slye  (1913), 
and  recent  statistics  emphasize  the  well-known  fact  of  family  predisposition  to  cancer 
in  human  beings.  Racial  immunity  to  cancer  has  been  shown  by  Levin  (1910)  to  be 
very  marked  in  the  American  Indians.  This  fact  applies  to  isolated  tribes  of  Indians 
living  upon  reservations  extending  from  the  northern  to  the  southern  limits  of  the 
United  States,  where  the  Indians  for  a  period  of  20  years  have  shown  almost  complete 
immunity  to  cancer,  whereas  the  whites  living  in  the  immediate  neighborhood  show 
the  usual  incidence  of  cancer  characteristic  of  the  white  inhabitants  of  the  country. 
That  such  immunity  is  a  special  immunity  to  cancer  and  not  a  general  resistance  to 
disease  is  indicated  by  the  fact  that  the  same  tribes  of  Indians  show  an  unusually  high 
mortality  from  tuberculosis. 


CARCINOMA   OF  THE  THYROID  IN  SALMONOID   FISHES.  453 

EXPERIMENTAL  PRODUCTION  OF  THE  DISEASE. 

TROUT  TUMOR  MATERIAL  IN  STANDING  WATER. 

The  contents  of  a  thyroid  tumor  of  a  trout  were  expressed  into  tap  water  and  brook 
trout  fry  in  the  sac  stage  were  introduced.  About  300  fry  were  used,  distributed  in  15 
shallow  open  dishes  each  with  from  i  to  2  liters  of  the  contaminated  water.  Eighty- 
five  fry  in  similar  dishes  constituted  the  control.  By  keeping  the  dishes  in  the  cold  the 
fry  were  maintained  for  23  days  without  change  of  water,  or  other  than  spontaneous 
surface  aeration.  During  this  period  a  loss  of  16  per  cent  occurred  on  the  fish  in  the 
tumor  water  and  11.7  per  cent  on  the  controls. 

After  removal  from  the  tumor  water  the  fry  and  their  controls  were  held  for  sev- 
eral weeks  in  flowing  tap  water  and  suffered  a  gradual  mortality.  Sections  of  the  thyroid 
region  of  these  fish  show  no  recognizable  difference  between  the  controls  and  those  fed 
the  thyroid  material.  Figure  13  shows  the  thyroid  of  a  control  fish  soon  after  the  food 
sac  had  been  absorbed. 

FEEDING  TROUT  THYROID  TUMOR. 

Fourteen  brook  trout  of  yearling  age  but  of  small  size,  reared  almost  entirely  on 
live  fish  food,  were  fed  nine  times  during  one  month  with  portions  of  fresh  thyroid  trout 
tumor.  The  fish  were  held  for  54  days  in  glass  jars,  containing  each  3  liters  of  water 
and  two  individuals.  The  water  was  changed  once  during  this  period.  The  tempera- 
ture ranged  from  a  little  above  the  freezing  point  to  17°  C.,  which  made  necessary  their 
removal  to  flowing  water.  They  had  received  no  other  food  than  tumor  material. 
When  transferred  there  was  no  external  evidence  of  thyroid  enlargement.  No  histo- 
logical  changes  in  the  thyroid  tissue  were  recognized  after  careful  comparisons  with  the 

controls. 

FEEDING  HUMAN  CANCER  LIVER. 

Under  the  same  general  conditions  as  in  the  preceding  experiment  12  trout  were 
fed  five  times  during  23  days  with  solid  human  cancer  material  from  metastatic  foci  in 
liver  of  gastric  carcinoma.  After  54  days  they  were  transferred  to  flowing  water.  All 
were  without  externally  visible  thyroid  change  and  showed  microscopically  the  same 
early  hyperplastic  stage  as  the  controls. 

CLOSED  CIRCULATION. 

In  order  to  experiment  further  with  normal  and  tumored  trout  in  unchanged  water, 
two  independent  aquarium  systems  were  established  for  using  the  same  water  over 
again  continuously  by  means  of  circulation,  aeration,  and  filtration.  Refrigeration  was 
also  provided  so  that  the  water  could  be  at  all  times  kept  at  a  suitable  temperature  for 
trout. 

During  5 1  days,  1 6  domesticated  brook  trout  were  fed  human  cancer  of  the  liver  on 
14  different  days,  and  became  reduced  to  8  fish  in  number.  The  thyroids  of  4  of  these 
were  affected  and  2  had  visible  tumors,  but  an  accident  prevented  the  controls  from 
covering  an  equal  period,  and  though  the  latter,  12  in  number,  were  all  clean  but  one, 
nothing  conclusive  is  to  be  inferred. 


454  BULLETIN  OP  THE  BUREAU  OF  FISHERIES. 

Fifty  clean  domesticated  yearling  brook  trout  were  placed  in  the  closed  circulation 
with  several  badly  tumored  trout.  In  over  four  months,  during  a  large  part  of  which 
the  water  was  aerated  artificially,  without  circulation,  we  did  not  succeed  in  producing 
any  notable  thyroid  reaction,  and  none  which  went  beyond  the  controls.  We  do  not 
believe  tumors  can  be  produced  by  contact  or  association  with  tumored  fish  in  this  way, 
at  least  not  in  any  reasonable  time.  (See  also  feeding  experiments  p.  100.). 

The  experiments  in  the  closed  circulation  add  to  those  in  standing  water  in  glass 
dishes  in  showing  that  the  pollution  of  the  water  by  the  fishes  themselves  and  their 
food  refuse  plays  little  if  any  part  in  the  thyroid  reaction.  A  number  of  trout  were  held 
for  113  days  in  a  63-gallon  aquarium  tank  with  only  four  changes  of  water.  Artificial 
aeration  was  maintained  by  a  constant  air  current  liberated  in  minute  bubbles  at  the 
bottom  of  the  tank.  The  fish  were  domesticated  yearling  trout,  but  not  of  a  readily 
susceptible  lot,  and  none  of  them  showed  any  external  sign  of  thyroid  change  at  the  end 
of  the  experiment.  The  fish  were  fed  on  liver,  ate  heartily,  and  were  in  good  condition 
thoughout  the  period. 

Most  brook  trout,  however,  held  in  troughs  at  the  laboratory  and  supplied  with 
Lake  Erie  water  tended  to  acquire  the  red  floor  of  the  mouth  when  fed  on  liver.  Such 
trout  kept  in  the  ice-cold  tap  water  in  the  winter  and  fed  nothing,  or  given  very  low 
feeding,  showed  within  a  few  weeks  signs  of  thyroid  regression.  Further  evidence  of 
such  regression  is  afforded  by  a  yearling  brook  trout  with  a  small  but  distinct  thyroid 
tumor  visible  at  the  isthmus.  It  was  placed  in  a  glass  jar  with  standing  water  in  the 
cold  and  kept  for  44  days  without  food.  The  water  was  changed  several  times.  The 
tumor  had  completely  disappeared  at  the  end  of  this  period. 

TRANSPLANTATION  AND  INOCULATION  EXPERIMENTS. 

Several  attempts  to  secure  a  new  autonomous  growth  by  implanting  portions  of 
visible  thyroid  tumors  in  normal  trout  have  been  made.  Both  wild  and  domesticated 
trout  have  been  used.  In  only  one  fish  have  we  met  with  partial  success  in  that  the 
graft  showed  evidence  of  proliferation  and  was  still  alive  at  the  end  of  three  months 
when  examined  microscopically. 

In  December,  1908,  a  number  of  supposedly  healthy  fish  were  sent  to  Buffalo  from 
St.  Johnsbury,  Vt.  These  were  inoculated  in  the  thyroid  region  with  a  suspension  of 
thyroid  tumors  from  fish  obtained  from  Bath.  The  surface  of  the  tumor  was  carefully 
sterilized  by  burning.  The  greatest  precautions  were  taken  to  prevent  contamination. 
The  center  of  the  soft  tumor  was  carefully  scraped  out,  rubbed  up  with  salt  solution, 
and  then  injected.  Nineteen  fish  were  thus  inoculated  and  later  transferred  to  the 
Bath  hatchery,  where  they  were  kept  in  the  troughs  of  the  fish-hatchery  building.  An 
examination  of  these  fish  in  the  autumn  of  1909  showed  that  all  of  them  had  visible 
tumors,  but  the  epidemic  of  1909  was  at  that  time  in  full  swing,  and  it  was  impossible 
to  determine  whether  the  development  of  tumors  was  due  to  the  inoculation  or  to  the 
simple  fact  that  these  fish  had  been  placed  in  the  infected  water  of  the  Bath  fish  hatchery. 

In  a  series  of  fish  inoculated  at  Bath  in  the  summer  of  1909,  in  most  of  which  the 
grafts  were  contaminated  and  sloughed  out,  one  fish  (no.  83),  which  was  inoculated  Sep- 


CARCINOMA  OF  THE  THYROID  IN  SALMONOID  FISHES.  455 

tember  i,  1909,  and  killed  for  examination  November  24,  1909,  showed  at  the  point  of 
inoculation,  which  was  in  the  muscular  structure  of  the  abdominal  wall,  just  anterior  to 
the  left  ventral  fin,  evidence  of  a  small  protruding  growth  the  size  of  a  grain  of  rice.  On 
sectioning  this  tissue,  a  slender  growth  is  found  extending  in  what  must  have  been  the 
track  of  the  needle.  Under  the  microscope  the  growth  is  made  up  of  a  series  of  nodules, 
most  of  them  with  a  not  very  well-defined  connective  tissue  capsule.  The  continuity 
of  the  epidermis  at  the  point  of  the  small  tumor  is  broken,  and  we  have  here  a  growth  of 
tissue  connected  with  the  nodular  growths  in  the  deeper  structures.  This  protrudes 
through  the  broken  continuity  of  the  epidermis.  The  circumscribed  nodules  lying  be- 
tween the  muscle  bundles  and  the  subcutaneous  tissue  are  made  up  of  large  spindle 
and  irregularly  shaped  cells.  The  centers  of  the  larger  nodules  contain  a  certain  amount 
of  hyaline  detritus.  Scattered  between  the  cells  of  the  nodules,  particularly  toward  the 
center,  are  many  leucocytes.  At  the  outer  margins  of  the  nodules  the  cells  are  best 
preserved.  The  nuclei  vary  greatly  in  size,  the  protoplasm  stains,  the  cell  boundaries 
are  not  always  well  defined.  The  growth  is  made  up  of  a  complex  of  cells  with  large 
vesicular  nuclei  containing  one  or  more  nucleoli.  They  may  be  recognized  as  thyroid  epi- 
thelium. In  a  nodule  which  fills  the  break  in  continuity  in  the  epidermis  there  is  a  dis- 
tinct suggestion  of  tubular  arrangement  with  a  definite  stroma  carrying  blood  vessels, 
and  at  the  margin  of  one  or  two  of  the  other  nodules  definite  alveoli  may  be  made  out. 

Toward  the  centers  of  the  nodules  there  is  distinct  evidence  of  atrophy  of  the  cells, 
associated  with  clumps  of  chromatin  and  hyaline  detritus.  There  are  many  cells  with 
very  large  nuclei.  There  is  generally  a  great  difference  in  the  size  and  shape  of  the 
nuclei.  Rarely  a  karyokinetic  figure  is  found.  The  cells  are  closely  packed  together, 
but  in  some  nodules  there  has  evidently  been  a  growth  of  capillaries  in  attempts  at  forma- 
tion of  a  stroma.  From  the  microscopic  picture  it  is  evident  that  there  has  been  some 
proliferation  in  the  implanted  tissue,  and  that  three  months  after  portions  of  the  graft 
at  least  are  still  alive. 

At  Craig  Brook  station  in  1910  implants  were  made  directly  into  the  thyroid  region 
of  the  fish  with  the  aid  of  a  hypodermic  needle.  It  was  found  that  the  trout  will  endure 
a  needle  puncture  in  the  floor  of  the  mouth  and  the  injection  of  one-fifth  cubic  centimeter 
of  physiological  salt  solution  directly  into  the  tissues  containing  the  thyroid  with  little 
reaction.  By  inserting  the  needle  a  little  to  one  side  of  the  median  line  the  ventral 
aorta  is  avoided,  and  most  of  them  show  no  external  bleeding.  Some  of  the  fish  suffer 
from  shock,  due  to  the  puncture,  from  which  they  recover  within  5  to  20  seconds.  Even 
those  which  bleed  usually  do  not  succumb.  Of  76  yearling  domesticated  trout  thus 
inoculated  as  controls,  only  i  died  as  a  result  of  the  manipulation.  The  fish  tumor 
material  for  inoculation  was  ground  up  and  mixed  with  its  own  volume  of  physiological 
salt  solution.  The  difficulty  in  planting  this  material  in  the  tissues  of  the  trout  lies  in 
the  high  toxicity  of  the  tumor  extract.  It  is  not  practicable  to  place  transplants  of 
ordinary  size  in  this  vascular  region  without  heavy  loss  from  toxemia.  The  tumor 
material  varies  considerably  in  toxicity.  Domesticated  trout  endure  the  mechanical 
injury  incidental  to  inoculation  better  than  wild  trout. 


BULLETIN  OF  THE   BUREAU  OF  FISHERIES. 

Of  30  wild  trout  injected  in  the  thyroid  region  with  2  minims  each  of  tumor 
ground  with  an  equal  volume  of  salt  solution,  about  half  died  from  the  immediate  toxic 
effect  of  the  injection.  At  another  trial  one-tenth  cubic  centimeter  of  material  made 
from  several  tumors  was  injected  into  each  of  15  domesticated  trout.  Eleven  of  them 
succumbed  almost  immediately.  The  material  was  then  diluted  until  it  contained  3 
volumes  of  salt  solution  and  15  more  fish  were  injected,  but  12  of  these  died  within  2  or 
3  hours.  Seven  fish  were  injected  subcutaneously  near  the  dorsal  fin  with  one-fifth 
cubic  centimeter  of  this  material,  and  5  died  within  a  short  time.  One  cubic  centimeter 
was,  however,  passed  into  the  stomach  of  i  trout,  and  one-half  cubic  centimeter  each 
into  the  stomachs  of  3  others  without  apparent  effect.  This  particular  sample  of  com- 
bined tumor  substance  was  unusually  toxic. 

The  trout  dying  from  the  immediate  physiological  effect  of  trout  tumor  substance 
ground  with  salt  solution  showed  a  fairly  characteristic  picture  of  symptoms,  ending  in 
tetany.  The  mechanical  effect  is  little,  as  shown  by  the  control  fish.  In  the  few 
cases  where  the  shock  from  trauma  is  apparent  the  fish  lies  on  its  back  or  side,  scarcely 
breathing,  and  recovers  in  a  few  seconds.  The  inoculated  fish,  however,  were  evidently 
poisoned.  They  became  immediately  distressed,  swam  in  circles  or  in  short,  frantic, 
and  aimless  dashes  about  the  trough,  then  fell  greatly  weakened  upon  their  sides  and 
lay  there  with  short  and  rapid  breathing  until  the  next  paroxysm.  Finally  they  suc- 
cumbed in  tetany,  some  with  gills  widely  distended  and  marked  opisthotonos.  Even 
the  survivors  seemed  to  be  much  weakened. 

Forty-three  wild  brook  trout  were  inoculated  in  the  thyroid  region  with  small 
portions  of  tumor  taken  directly  from  the  fish  without  grinding  or  mixing  with  salt 
solution.  Pieces  were  forced  through  the  floor  of  the  mouth  by  means  of  trochar,  probe,  or 
seeker.  The  material  was  more  or  less  toxic  even  in  this  form,  and  the  mechanical  injury 
and  bleeding  were  greater  than  with  the  needle,  but  24  of  the  43  trout  survived. 

Ten  domesticated  brook  trout  were  injected  in  the  thyroid  region  with  one-fifth  of  a 
cubic  centimeter  each  of  a  mixture  of  one  volume  of  domesticated  brook  trout  blood 
and  three  volumes  of  physiological  solution.  No  loss  attended  the  operation,  and  the 
fish  have  never  shown  any  but  the  immediate  reaction  to  the  inoculation. 

In  all  injections  and  inoculations  the  instruments  used  were  sterile,  and  the  tumor 
material  obtained  as  free  from  contamination  as  possible.  It  is  not  usually  possible  to 
obtain  in  quantity  the  thyroid  tumor  material  from  fish  in  a  completely  aseptic  condition. 

Mud  from  one  of  the  fish  ponds  (no.  10)  constantly  associated  with  tumor  fish  was 
injected  into  the  stomachs  of  25  domesticated  trout  and  of  20  wild  trout.  The  dose 
was  repeated  on  the  former  lot  after  three  days.  The  filtrate  of  this  mud  through  paper 
was  injected  into  the  thyroid  region  of  25  domesticated  trout  and  behind  the  eyeball 
of  17  domesticated  trout.  The  dose  was  2  to  2^3  minims.  These  fish  have  shown  no 
results  from  the  inoculations. 

Trout  tumor  material  has  been  ground  with  sand  and  filtered  through  a  Berkfeld 
filter.  The  filtrate  has  been  injected  into  the  thyroid  region  of  2-year-old  domesticated 
trout,  all  manipulations  being  carried  on  in  the  cold.  About  0.3  to  0.4  cubic  centimeter 
of  filtrate  was  given  each  of  9  trout.  These  were  kept  under  observation  for  over  four 


CARCINOMA  OF  THE  THYROID  IN  SALMONOID   FISHES.  457 

months,  when  one  thyroid  tumor  and  two  red  floors  had  developed  among  them.     The 
controls  had  been  previously  lost  from  some  unknown  cause,  leaving  the  result  negative. 

EXPERIMENTAL  INDUCTION  OF  CARCINOMA." 

In  June,  1910,  about  2,400  wild  brook  trout  of  various  sizes  were  collected  in  the 
wilderness  of  Wisconsin  by  the  Bureau  of  Fisheries  and  brought  to  Craig  Brook  station. 
They  were  held  in  Craig  Brook  above  all  fish  cultural  operations  until  used  in  experi- 
ments. Several  specimens  were  sectioned  from  time  to  time  and  found  to  be  entirely 
normal.  A  series  of  16  new  cement  tanks,  2.7  by  i  by  i  meters  in  size,  which  had  not 
previously  held  fish,  were  used  as  containers  for  the  experimental  lots.  (Fig.  79  left.) 
The  depth  of  water  in  these  tanks  was  0.8  meter  and  the  inflow  50  to  60  liters  per 
minute.  In  July,  1910,  n  lots  each  of  50  adult  wild  trout  from  Wisconsin  were  placed 
in  1 1  of  these  tanks  and  feeding  experiments  begun  with  a  variety  of  foods,  which  were 
maintained  for  each  lot  throughout  the  experiment  without  change.  The  so-called 
natural  food  was  not  all  of  one  kind,  but  consisted  of  fresh-water  mussels,  fresh-water 
fish,  and  in  the  summer  maggots  of  flies.  The  vegetable  food  was  screenings  from 
miscellaneous  grains.  In  September,  1910,  certain  of  the  lots  were  augmented  by  smaller 
wild  trout  from  Wisconsin,  which  had  received  food  corresponding  to  the  lots  to  which 
they  were  added,  or  natural  food. 

Table  vm  summarizes  these  feeding  experiments  and  includes  some  smaller  lots 
which  were  inoculated  in  various  ways,  and  were  fed  natural  food.  Such  lots  were 
negative,  and  are  in  effect  controls  to  the  feeding  experiments.  The  inoculated  lots 
are  discussed  under  a  separate  heading.  Lot  2149  was  an  attempt  to  crowd  the  fish 
by  confining  them  in  one-third  of  the  tank.  Lot  2155  aimed  at  excess  feeding. 

Lots  2150  and  2151  were  practically  wiped  out  by  the  unsuitable  food,  to  which  the 
wild  trout  could  not  adapt  themselves  readily.  The  wild  trout  gradually  became 
accustomed  to  the  fish  cultural  foods,  liver  and  heart,  and  finally  thrived  upon  them 
about  as  domesticated  trout  do.  On  examination  after  four  months,  and  again  after 
one  year,  all  the  fish  were  clinically  clean,  without  any  external  evidence  of  thyroid 
disease.  At  the  examination  after  one  year  the  thyroid  region  of  from  one  to  three 
fish  from  each  tank  was  prepared  for  microscopic  study,  and  the  histology  of  each  is 
shown  below  by  a  description  of  each  section  by  number  (table  vm).  The  diagnoses  may 
be  briefly  summarized  as  follows: 

In  the  lots  fed  raw  liver  (fig.  84)  and  heart  (fig.  85)  a  general  hyperplasia  existed 
with  early  carcinoma  in  a  few  cases;  the  two  fish  from  lot  2155  were  exceptional,  appear- 
ing normal.  The  lot  fed  cooked  liver  had  remained  normal.  (Fig.  87.)  Those  fed 
marine  fish  (fig.  88),  vegetable  food  (fig.  89),  and  natural  food  (fig.  86)  were  entirely 
without  hyperplasia.  Nearly  all  remained  normal,  but  a  few  showed  a  considerable 

»  We  believe  that  these  experiments,  reported  at  the  fifth  annual  meeting  of  the  American  Association  for  Cancer  Research, 
Aprils  and  4,  1912,  in  Philadelphia,  and  reported  in  the Zeitschrift f iir  Krebsforschung.  Band  12,  Heft  a,  1912,  p.  436,  under  the 
title,  "  Relation  of  Feeding  to  Thyroid  Hyperplasia  in  the  Sahnonidae,"  by  H.  R.  Gaylord  and  M.  C.  Marsh,  Buffalo,  constitute 
the  first  instance  in  which  spontaneous  cancer  has  been  experimentally  induced  tinder  properly  controlled  conditions  in  the 
lower  animals.  They  antedate  the  recent  experiments  of  Fibiger  in  the  production  of  carcinoma  of  the  stomach  and  esophagus 
in  rats  by  feeding  them  nematodes  from  cockroaches,  for  which  a  similar  claim  has  been  made. 

8207°— 14 7 


458  BULLETIN   OF  THE   BUREAU   OF  FISHERIES. 

increase  in  the  number  of  thyroid  follicles  without  elevation  of  epithelium  or  other 
changes  from  the  normal.  Lot  2163  was  exceptional  in  that  two  of  three  fish  showed 
beginning  hyperplasia.  They  had  been  inoculated  with  trout  tumor  material  in  the 
thyroid  region,  the  implant  failing  to  take. 

At  the  examination  of  June,  1912,  two  years  after  the  beginning  of  the  experiment, 
one  distinct  thyroid  tumor  (fig.  90)  had  developed  in  lot  2146  under  the  feeding  of  raw 
heart  muscle.  This  fish,  and  one  lot  2147,  which  was  fed  raw  liver  and  had  developed 
a  red  floor,  with  slight  swelling,  showed  typical  thyroid  carcinoma.  Of  the  rest  many 
had  developed  red  floors,  as  shown  in  table  vin.  One  or  more  specimens  were  preserved 
from  each  lot,  and  a  description  of  the  histology  of  the  thyroid  is  given  below.  The 
trout  fed  with  marine  fish,  vegetable,  and  natural  food  still  remained  normal,  while  carci- 
noma has  definitely  developed  in  two  of  the  sample  fish  fed  raw  animal  food.  Those  fed 
cooked  liver  have  passed  through  hyperplasia  to  regression  and,  in  fact,  the  chief  char- 
acteristic of  the  microscopic  picture  in  all  the  fish  on  meat  diet  is  the  regression  indi- 
cative of  spontaneous  recovery.  (Fig.  91-92.) 

In  general,  it  may  be  stated  that  the  results  obtained  by  selected  feeding  are  in 
accord  with  our  experiences  in  the  study  of  hatchery  conditions  and  that  the  relation 
of  foodstuffs  to  the  incidence  of  the  disease  is  contributory  and  not  causative.  Thus 
raw  liver  and  raw  ox  heart  used  as  a  food  act  as  a  predisposing  factor  in  the  develop- 
ment of  carcinoma  of  the  thyroid.  Cooking  the  same  food  tends  to  delay  the  advent 
of  the  disease  and  fish  fed  upon  natural  food,  marine  fish,  and  vegetable  food  are  able 
to  resist  the  disease  for  a  considerable  period  of  time,  if  not  indefinitely.  One  might 
conclude  from  these  experiments  that  raw  liver  and  raw  heart  muscle  were  the  sole 
cause  of  the  disease,  were  it  not  for  the  fact  that  we  are  able  to  check  this  observation 
by  an  observation  made  at  another  hatchery  where  the  conditions  are  practically 
reversed.  In  this  hatchery  all  of  the  fish  are  fed  upon  raw  liver  and  raw  ox  heart  muscle; 
but  the  fish  kept  in  one  water  supply  are  free  from  the  disease  with  this  type  of  feeding, 
whereas  those  kept  in  other  tanks  with  a  slightly  different  water  supply  are  uniformly 
affected  by  the  disease.  This  state  of  affairs  exists  at  Cold  Spring  Harbor,  N.  Y.  The 
hatchery  building  is  supplied  with  water  from  an  artesian  pipe  driven  near  the  building. 
The  overflow  from  the  hatchery,  and,  of  course,  from  the  artesian  supply,  which  is  not 
required  for  the  hatchery  building,  flow  into  a  series  of  large  earth  ponds,  and  then 
a  series  of  concrete-lined  ponds.  The  arrangement  of  the  concrete  ponds  is  such  that 
one  pond  is  practically  continuous,  each  division  for  fish  being  separated  from  the  one 
above  it  by  an  arrangement  of  boards  over  which  the  water  flows.  The  ponds  and 
concrete  tanks  are  old  and  at  the  time  of  examination  were  lined  with  a  visible  growth 
of  green  algae. 

Young  fish  hatched  in  the  hatchery  in  the  artesian  water  were  placed  for  the  most 
part  in  the  concrete  tanks  just  mentioned,  but  in  a  few  instances  the  lots  were  divided 
and  approximately  half  were  placed  in  a  spring  located  a  distance  of  several  hundred 
yards  from  the  hatchery  building.  This  spring  flowed  out  from  a  hillside  obviously 
from  the  same  general  supply  as  the  artesian  water  and  the  springs  near  the  hatchery. 


CARCINOMA  OF  THE  THYROID  IN  SAI.MONOID  FISHES.  459 

In  the  small  brook  about  100  yards  in  length  wooden  divisions  and  tank-like  arrange- 
ments had  been  constructed.  In  these  the  young  fish  were  placed  and  all  the  fish  both 
in  the  old  concrete  tanks  and  in  the  spring  were  fed  with  chopped  raw  beef  liver  and 
ox  heart  muscle.  An  examination  of  specimens  taken  from  the  two  sources  in  the 
autumn  of  1911,  of  fish  respectively  6  and  18  months  old,  taken  from  both  sources, 
showed  that  whereas  the  fish  in  the  old  concrete  ponds  had  well-defined  hyperplasia 
(fig.  93),  those  kept  in  the  spring  water  had  thyroids  exactly  like  those  found  in  wild 
fish  (fig.  94),  although  both  had  been  liberally  fed  upon  raw  liver  and  ox  heart.  From 
this  observation  we  must  conclude  that  the  selective  feeding  experiments  at  Craig 
Brook  station  indicate  that  the  feeding  of  raw  ox  heart  and  liver  produce  conditions 
either  in  the  tanks  or  in  the  fish  themselves  which  favor  the  development  of  the  disease, 
but  that  such  feeding  of  raw  heart  muscle  and  liver  is  not  the  direct  cause  of  the  disease. 
It  is  hard  to  understand  why  fish  fed  upon  cooked  liver  should  have  resisted  the  disease 
so  much  longer  than  those  fed  upon  the  uncooked  liver,  unless  it  is  possible  that  the 
agent  causing  the  disease  is  sometimes  or  usually  transmitted  with  the  uncooked 
materials,  or  that  cooking  the  material  delays  decomposition  and  thus  favors  a  more 
hygienic  condition  in  the  tanks.  The  complete  resistance  of  fish  fed  upon  natural 
food,  chopped  marine  fish,  and  vegetable  food,  all  of  which  were  obtained  from  sources 
entirely  different  from  either  the  heart  muscle  or  liver,  would  rather  suggest  that  these 
sources  of  food  are  free  from  the  possible  contamination  with  the  agent  of  the  disease  ; 
or,  again,  that  they  are  not  so  easily  decomposed  in  the  tanks  and  do  not  therefore 
contribute  to  a  favorable  condition  for  the  propagation  or  development  of  the  agent 
in  the  tanks. 

McCarrison  (1906)  points  out  that  in  Chitral  where  goiter  is  endemic  the  people 
are  for  the  most  part  poor.  Food  is  plentiful,  comparatively  speaking,  from  July  to 
February,  after  which  the  people  are  obliged  to  live  on  the  poorest  grains,  dried  fruits, 
and  the  green  stuffs  of  the  spring.  Their  food  is  entirely  vegetable.  Flesh  meat  is  an 
article  of  diet  far  beyond  their  means,  while  salt  is  a  luxury  to  all  except  the  richest 
families. 

That  the  disease  may  be  introduced  into  a  community  where  it  has  not  previously 
been  and  that  in  such  cases  the  water  supply  becomes  at  once  the  suspected  agent  of 
distribution  is  shown  by  McCarrison's  remarkable  observation  in  Nagar. 

In  the  village  of  Nagar  goiter  was  unknown  six  years  ago.  Nagar  is  a  small  State  situated  up  one 
of  the  many  side  valleys  on  the  left  bank  of  the  Gilgit  River.  It  will  be  remembered  as  the  scene  of  a 
smart  frontier  rising  in  1893.  It  was  after  this  year  that  the  little  State  of  Nagar  began  to  be  opened  up; 
previously,  jealous  of  its  independence  and  at  war  with  its  immediate  neighbors,  it  was  careful  to 
exclude  foreigners.  During  recent  years  intercourse  with  the  outside  world  has  become  more  free, 
but  still  there  is  a  decided  prejudice  against  the  settling  of  foreigners  in  this  little  hill  State. 

Some  five  years  ago  certain  cases  of  goiter  were  introduced  from  without,  and  since  then  the  disease 
has  begun  to  gain  a  footing.  It  may  be  as  well  to  indicate  clearly  that  there  can  be  no  doubt  about 
the  fact  that  goiter  was  quite  unknown  six  years  ago.  The  fact  that  it  has  gained  a  footing  in  his  territory 
is  a  matter  of  very  considerable  anxiety  to  the  present  rajah,  and  through  his  help  I  was  enabled  to  go 
into  the  matter  with  great  care.  All  the  important  men  of  the  State,  the  rajah  himself,  councilors, 
priests,  etc.,  assure  me  that  no  case  of  goiter  ever  originated  in  Nagar  till  within  the  last  six  years. 


460  BULLETIN  OP  THE  BUREAU  OP  FISHERIES. 

There  is  a  family  at  present  at  Nagar  which  consists  of  nine  souls;  of  these  three  came  from  Gilgit 
some  years  ago,  all  suffering  from  goiter.  Two,  the  father  and  the  mother,  have  no  goiters;  the  father 
came  from  Gilgit.  The  remaining  four  individuals  have  never  been  outside  Nagar.  Three  are  high- 
caste  Mohammedan  girls  (16,  15,  and  10  years  of  age),  which  makes  the  statement  the  more  likely  to  be 
accurate.  The  fourth  individual  is  a, boy  aged  12;  he  has  never  been  outside  Nagar.  All  of  these  four 
developed  goiter  about  two  years  ago.  This  family  lives  in  the  same  house,  that  is,  the  same  room, 
eat  out  of  the  same  vessels,  etc.  It  is  to  be  observed  that  these,  the  first  victims,  are  all  young. 

Another  family  consists  of  a  man,  his  wife,  and  son,  aged  2,  and  the  man's  brother,  aged  20.  The 
man  brought  goiter  with  him  from  outside  five  years  ago.  Two  years  later  his  brother  developed  the 
disease,  though  he  had  not  been  outside  Nagar  for  five  years.  The  little  boy,  aged  2,  developed  the 
disease  one  year  ago;  the  wife  is  free  from  it.  Another  man,  aged  23,  brought  the  disease  from  Gilgit 
one  year  ago;  it  is  increasing  in  size  here. 

Twelve  children,  all  under  10  years  of  age,  were  brought  to  me  having  marked  enlargements  of  the 
gland.  There  are  no  other  cases  of  the  disease  in  Nagar.  The  children  were  from  different  houses 
scattered  over  the  village.  The  first  family  to  which  I  referred  lives  at  the  head  of  the  spring  which 
supplies  the  village  with  drinking  water. 

The  village  supply  consists  of  a  spring  which  comes  out  of  the  hills;  it  is  not  the  only  supply  of  the 
village.  The  cases  I  have  referred  to  all  drank  from  this  water.  This  spring  is  said  to  have  been  in 
existence  from  time  immemorial;  the  chemical  composition  of  its  water  has  presumably  not  altered. 
The  conditions  of  life  of  the  people  are  the  same.  The  only  added  factor  in  the  case  is  the  introduction 
of  the  disease  from  without.  That  it  is  spreading  there  can  be  no  doubt,  and  that  the  course  of  the  spread 
is  a  typically  endemic  one  is  equally  evident.  It  is  easy  to  understand  why  the  disease  should  not 
have  reached  Nagar  earlier,  as  it  is  only  within  recent  years  that  the  communications  of  Nagar  with  the 
outside  world  have  become  free. 

It  appears  evident  also  that  it  is  by  means  of  the  spring  water  that  the  disease  is  now  spreading, 
for  the  12  children  are  residents  of  that  part  of  Nagar  supplied  by  the  spring,  and  their  homes  are  scat- 
tered here  and  there  among  the  houses  of  the  yet  unaffected  inhabitants.  Further,  the  fact  that  the 
first  family  referred  to  lives  at  the  head  of  the  spring  is  of  importance,  and  also  that  no  cases  of  this 
disease  were  observed  where  water  from  other  sources  only  is  drunk,  that  is,  in  the  distant  parts  of  the 
village  where  the  nullah  water  or  the  river  water  is  used. 

It  seems  likely,  therefore,  that  some  poison,  goiter  producing  in  its  powers,  has  been  introduced 
into  a  water  supply  which  happened  to  be  suitable  for  the  conveyance  of  this  disease. 

This  case  of  Nagar  can  not  be  explained  by  any  theory  which  attributes  to  dissolved  ingredients 
In  a  water  goiter-producing  properties;  nor  can  inorganic  matters  in  suspension  account  for  this  outbreak; 
for  it  can  not  be  supposed  that  from  causes  in  the  water  which  have  existed  from  time  immemorial  a 
disease  should  suddenly  spring.  There  is,  to  my  mind,  only  one  explanation,  namely,  the  introduction 
of  an  organism  into  the  water  supply. 


I 


CARCINOMA   OF  THE   THYROID  IN   SALMONOID   FISHES. 
TABLE  VIII. — FEEDING  AND  OTHER  EXPERIMENTS  WITH  WILD  BROOK  TROUT. 


461 


Tank. 

Lot. 

Fish. 

Food. 

Other  conditions. 

Fish 
added 
Sept.  21, 
1910. 

Clinical  condition,  June,  1913.0 

Remain- 
ing. 

Clean. 

With  red 
floors. 

With  tu- 
mors. 

2146 
2147 
2148 

5° 
50 

Heart,  raw.  .  . 

0 

27 
5 
14 
4 

0 

25 
7 
o 
13 
26 
o 
o 
o 

o 

0 

o 

J39 
34 

I 
37 
I 
o 

20 
36 

C») 

38 

40 

22 

9 

12 

16 

12 

4 

21 

3° 
o 
26 

I 

17 
4 

i 
ii 

0 

X 

o 
o 
o 

0 

Liver,  raw. 

Marine  fish  .  .  . 

4  

2149 
2150 

5° 
5° 

Liver,  raw.  .  .  . 
Vegetable 

Reduced  space;  crowding  

6  

.do  

In  presence  of  tumor  fish  

2152 
2153 

5° 

Liver,  cooked  . 
Liver,  raw  . 

16 

28 

4 
8 

0 
0 

o 

0 

o 
o 

0 
0 

o 
o 

0 

8  

In  presence  of  tumor  fish  

9  

10  

II  

2154 
2155 
2156 

SO 
5° 
5° 

Natural  food.  . 
Liver,  raw  .... 
Natural  food  .  . 
.    do..  . 

Minimum  feeding  
Forced  feeding  
Controls  

PrmH  in  Trmrl  in  tank 

35 
40 

21 

S 

12 

15 

9 
3 

3 
o 

i 
4 
o 

i 
3 

I 

13  upper. 
13  lower  .  . 

2160 

16 

..      do..  . 

Controls  for  tanks  12-16  

....  do.... 

Inoculated   in    thyroid   r 
with  trout  thyroid  tumc 
Pond  10  mud  in  stomachs 
Inoculated    in    thyroid    r 
with  trout  thyroid  tumc 
Inoculated  behind  eye  wi 
trate  from  pond  10  mud 

egion 
r. 

14  

do 

do 

egion 
r. 
hfil- 

16  

2164 

I? 

do  

Tank. 

Sec- 
tious, 
1911. 

Diagnoses,  1911. 

Seo 
tions, 
1912. 

Diagnoses,  1912. 

20OO 
2001 

2O02 
2003 

A,  h> 
A,  be 

nor 
Norrr 
Begir 
A,  B 

perplasia;  B,  ca 
ginning  hyperp 
na. 
al 

2098 
2099 

2100 
2IOI 
2IO2 

A,  tumor,  carcinoma;  B,  adeno-carcinoma. 
A,  B,  C,  regression. 

Normal. 
Regression. 
Normal. 

Regression. 
A,  B,  regression. 
Normal. 
Regression. 
Normal. 
Increased  thyroid  of  normal  type. 
Increased  thyroid  of  normal  type. 
Normal. 
A,  normal;  B,  increased  thyroid  of  normal  type. 
Increased  thyroid  of  normal  type. 
Increased  thyroid  of  normal  type. 

asia;  B,  normal;  C,  carci- 

C,  normal  

6 

2OO5 
2OO6 
2OO7 
2008 

Norrr. 
A,  B 
A,  B 
A   B 

tal           .                               .... 

2103 
2104 
2113 
2IO5 
2IO6 
2IO7 
2108 
2IO9 
2110 
2III 
2112 

8  

beginning  hyperplasia  
C.  normal.  .  . 

A   B,  normal  

B  ,  C,  normal  

A,  B,  C.  normal  

13  upper. 
13  lower  .  . 

2OI2 
2013 

A,  B 
A,  B, 

normal  
al  

2015 
2Ol6 

A,  no 

Norm 

rmal;  B,  C,  beginning  hyperplasia  
al  

16  

Examinations  of  Nov.  30,  1910,  and  July,  1911,  all  were  clean. 


6  Transferred  to  pond  10. 


DESCRIPTION  OF  SECTIONS  TO  ACCOMPANY  TABLE  VIII. 

2000  B.  Tubulo-alveolar  type  of  carcinoma.     Marked  infiltration  of  surrounding  areolar  tissue.    Infiltration  of  muscle  above 
into  bone  spaces  and  infiltration  of  vessel  wall.    Invasion  of  cartilage. 

2001  A.  Beginning  hyperplastic  stage.    Certain  follicles  are  lined  with  columnar  epithelium.    In  many  such  follicles  colloid  is 
absent,  in  others  present  but  poorly  stained.    Surrounding  this  group  of  follicles  are  follicles  of  strictly  normal  appearance.    Epi- 
thelium flattened,  filled  with  colloid.     Beginning  of  the  hyperplasia  in  this  specimen  is  evidently  limited  to  individual  follicles 
(Fig.  84.) 

2001  B.  Most  of  the  thyroid  tissue  in  this  specimen  is  of  typical  normal  appearance,  flattened  epithelium,  follicles  filled  with 
stainable  colloid. 

2001  C.  The  entire  space  surrounding  the  vessel  is  filled  with  closely  packed  alveoli,  small  sized  alveolar  structures  lined  with 
high  columnar  epithelium,  with  deeply  staining  vesicular  nuclei.  Colloid  is  almost  entirely  absent.  Evidently  growth  of  the 
thyroid  tissue  which  has  spread  upward  into  the  areolar  tissue  immediately  below  the  mucosa  of  the  floor  of  the  mouth.  Under 
high  power  the  nuclei  present  great  variability  in  size,  the  staining  qualities  are  vesicular  with  one  or  two  nucleoli.  Marked 
evidence  of  hyperemia  between  the  follicles.  Many  tubules  are  filled  with  closely  packed  cells.  In  some  portions  of  the 
growth  all  alveolar  structure  has  disappeared  and  small  islands  of  closely  packed  cells  are  found.  Infiltration  of  dense  con- 
nective tissue  structure,  perichondrium  and  periosteum.  Beginning  carcinoma  of  tubulo-alveolar  type. 


462 


BULLETIN   OF  THE   BUREAU   OF  FISHERIES. 


2002  B.  The  amount  of  thyroid  tissue  surrounding  the  vessels  is  very  scarce.    Vesicles  small,  epithelium  flattened,  filled  •with 
stainable  colloid.    Normal  thyroid. 

2003  A.  Alveoli  small  and  lined  with  high  columnar  epithelium,  deeply  staining  nuclei.    Colloid  absent.     Follicles  few  in 
number  and  poorly  staining.    Occasional  groups  of  vesicles  of  normal  appearance.    Beginning  invasion  of  areolar  tissue.    Dense 
connective  tissue  structure.    Growth  into  bone  cavities.     Definite  alveolo-tubular  type  beginning  carcinoma. 

2004  A,  B,  C.  Space  about  vessels  rather  well  filled  with  small-sized  vesicles  relatively  uniform  in  size.    Epithelium  is  flat. 
tened.    Vesicles  are  filled  with  stainable  colloid.    In  one  small  area  close  to  a  large  vessel  area  half  dozen  follicles  in  which  the 
colloid  is  small  in  amount,  the  epithelium  cubical.    Normal  thyroid. 

2005  A.  This  is  evidently  one  of  the  tumor  fish  introduced  into  this  experiment.    Large  amount  of  thyroid  tissue.    Great 
variability  in  the  size  of  the  follicles.     Large  regular  shaped  follicles  lined  with  flattened  epithelium  and  filled  with  stainable  colloid. 
Large  numbers  of  small  follicles  with  cubical  or  flattened  epithelium.    Varying  amount  of  colloid.    Large  amount  of  hyaline  con- 
nective tissue  stroma.    Obviously  a  tumor  which  has  undergone  regression.    Tumor  tissue  fills  the  entire  space  around  the  vessel, 
penetrates  to  the  floor  of  the  mouth,  and  into  the  bone  cavities.    It  has  previously  invaded  and  destroyed  large  areas  of  muscle. 
Contains  numerous  nematode  tubercles,  in  which  no  worms  are  to  be  found.    Spontaneous  recovery.    See  further  under  that 
heading. 

2005  B.  Very  few  follicles  included  in  this  section.  Flattened  epithelium  filled  with  stainable  colloid.  Typical  vesicles. 
Normal. 

2005  C.  Evidently  tumor  fish  introduced  into  this  experiment  with  spontaneous  recovery  like  2005  A.    Contains  two  nema- 
tode tubercles,  in  one  of  which  remnants  of  a  worm  can  be  seen. 

2006  A,  B.  Thyroid  consists  of  typical  vesicles  with  flattened  epithelium  filled  with  stainable  colloid.    Normal. 

2007  A.  Space  around  the  large  vessels  contains  scattered  follicles  filled  with  stainable  colloid,  lined  for  the  most  part  with 
flattened  epithelium.     There  is  marked  hyperemia,  marked  engorgement  of  the  vessels  between  the  follicles,  and  evidence  of 
small  extravasation  about  the  follicles.    A  few  follicles  are  lined  with  cubical  epithelium.    Hyperemia  of  the  thyroid,  possibly 
beginning  hyperplasia. 

2007  B.  Tissue  badly  preserved,  evidently  overheated  in  embedding.    Shows  section  of  media  of  aorta  around  which  are 
areas  of  closely  packed  large  follicles,  lined  with  cubical  epthelium.    No  colloid.    Beginning  hyperplasia. 

2008  A,  B.  Small  follicles  lined  with  flattened  epithelium,  filled  with  stainable  colloid.    Normal. 

2008  C.  Thyroid  tissue  in  this  fish  consists  of  rather  compact  masses  in  the  region  of  the  large  vessels.    The  epithelium  of 
some  follicles  is  slightly  cubical.    Follicles  are  filled  with  stainable  colloid.    Some  evidence  of  hyperemia  hi  the  vessels  between 
the  follicles.    Slight  hyperemia  of  the  thyroid.    Probably  normal. 

2009  A,  B.  Follicles  oval  and  spherical,  lined  with  flattened  epithelium,  filled  with  stainable  colloid.     Normal. 

2010  B.  Vesicles  lined  with  flattened  epithelium,  filled  with  stainable  colloid.     Normal.     Around  the  large  vessels  the  thyroid 
follicles  are  closely  packed;  the  colloid  is  reduced  in  amount  but  stains  deeply.    Epithelium  is  small,  cubical.    Probably  normal. 
Thyroid  tissue  greatly  increased  in  amount  but  of  normal  appearance. 

zoio  C.  Spherical  and  oval  follicles  lined  with  flattened  epithelium  filled  with  stainable  colloid.     Normal. 

201 1  A.  Follicles  lined  with  flattened  epithelium,  filled  with  stainable  colloid.    Between  the  follicles  hyperemia  of  the  ves- 
sels.   Some  evidence  of  extravasation.     Hyperemia  of  the  thyroid.     Probably  normal. 

2011  B,  C.  Spherical  and  oval  follicles  lined  with  flattened  epithelium,  filled  with  stainable  colloid.     Normal. 

2015  B.  Closely  packed  follicles  of  irregular  shape  with  almost  complete  absence  of  colloid.  Follicles  lined  with  cubical 
epithelium.  Small  groups  of  detached  follicles  lying  outside  the  closely  packed  area  lined  with  flattened  epithelium  and  filled 
with  stainable  colloid.  First  evidences  of  hyperplasia.  Beginning  simple  hyperplasia. 

2015  C.  Between  the  second  and  third  gill  arches  the  space  is  filled  with  loosely  arranged  follicles,  many  of  which  contain 
stainable  colloid  and  are  lined  with  slightly  cubical  epithelium.  Between  the  follicles,  marked  hyperemia  and  engorgement  of 
the  vessels.  Away  from  this  mass  in  this  area  of  slightly  altered  thyroid  one  finds  isolated  typical  normal  follicles  with  deeply 
staining  colloid  and  flattened  epithelium.  Again,  about  the  aorta  above  and  below  it,  one  finds  one  or  two  aggregates  of  follicles 
with  slightly  cubical  epithelium  and  evidences  of  hyperemia.  The  remainder  of  the  thyroid  tissue  about  the  large  vessels  strictly 
normal.  Hyperemia  of  the  thyroid,  possibly  beginning  hyperplasia.  Unusual  amount  of  thyroid  tissue. 

2098  A.  Tumor.  Typical  alveolo-solid  carcinoma  for  the  most  part,  with  areas  of  papillary  formation.  Infiltration  of  muscle, 
bone,  and  cartilage.  Infiltration  of  wall  of  vein.  Papillary  adenoi-carcinoma  infiltrating  muscle  bone  and  cartilage.  Hyaline 
degeneration  of  the  wall  of  the  media  of  the  aorta.  (Fig.  90.)  ^ 

2098  B.  Beginning  adeno-carcinoma  of  tubulo-alveolar  type.    Infiltration  of  areolar  tissue,  dense  connective  tissue  structures, 
periosteum  of  bone  and  muscle. 

2099  A.  Examination  of  this  section  shows  an  unusual  amount  of  thyroid  tissue  about  the  large  vessels,  small  follicles  lined 
with  flattened  epithelium,  some  of  them  containing  stainable  colloid,  others  poorly  stained  colloid,  many  of  them  empty,  pushed 
in  flattened  strands  between  the  dense  connective  tissue  structures,  spreading  well  forward  into  the  areolar  tissue  and  in  the 
adjacent  bone  cavities.     (Fig.  91.)    Great  increase  in  the  amount  of  thyroid  tissue.     Only  one  or  two  large  follicles  filled  with 
stainable  colloid.    Immediately  adjacent  to  the  large  vessels  a  few  follicles  with  high  cubical  epithelium  and  no  colloid.    The 
Whole  specimen  indicates  the  previous  existence  of  well-developed  hyperplasia  followed  by  regression. 

2099  B,  C.  Presents  the  same  histological  characteristics.  Increased  amount  of  thyroid  tissue.  Many  isolated  groups 
widely  distant  from  the  large  vessels.  About  the  large  vessels  are  many  tortuous  elongated  and  branching  alveoli  of  tubular 
type,  lined  with  flattened  epithelium,  free  from  colloid.  (Fig.  92,  under  "Spontaneous  Recovery.")  Colloid  almost  entirely 
absent. 


CARCINOMA  OP  THE  THYROID  IN  SALMONOID   FISHES.  463 

2101  A.  Small  closely-packed  follicles  lined  with  flattened  and  low  cubical  epithelium.  No  colloid.  Marked  increase  in 
amount  of  thyroid  tissue.  Many  follicles  and  flat  strands  of  follicles  between  the  muscle  bundles  in  the  areolar  tissue,  floor  of 
the  mouth,  and  bone  cavities.  Regression  from  well-developed  hyperplasia. 

2103  A.  About  the  large  vessels  are  individual  follicles  lined  with  columnar  epithelium,  filled  with  faintly  staining  colloid. 
These  follicles  are  irregular  in  shape.    Slight  infoldings  of  the  vesicular  wall  with  beginning  bud  formation.     Protoplasm  of  the 
cells  stains  deeply.    The  nuclei  are  vesicular,  of  great  variety  of  size.    The  long  axes  of  the  nuclei  are  perpendicular  to  the  cir- 
cumference.   Marked  hyperemia  of  the  small  vessels  between  these  follicles.    In  the  same  field  by  low  power  may  be  seen 
individual  follicles  of  typical  normal  appearance,  flattened  epithelium  filled  with  deeply  stainable  colloid.    We  have  here 
beginning  focal  hyperplasia.    Certain  groups  of  follicles  are  lined  with  flattened  epithelium,  contain  no  colloid,  are  elongate, 
branching  or  irregular  in  shape,  and  present  an  appearance  suggesting  regression  of  individual  follicles. 

2104  A,  B.  Marked  increase  of  thyroid.     Follicles  closely  packed  and  spherical,  some  filled  with  stainable  colloid.    Some 
follicles  of  irregular  shape  or  branching.    Widely  scattered  follicles  in  the  areolar  tissue  and  between  the  fibers  of  the  dense 
connective  tissue  structures.    Regression  of  hyperplasia. 

mi  A.  Spherical  and  oval  follicles  filled  with  stainable  colloid  and  lined  with  flattened  epithelium.  Engorgement  of  the 
vessels  between  the  follicles.  Slight  hyperemia.  Normal. 

CHEMOTHERAPY.-1 

THE  EFFECT  OF  IODINE.  MERCURY.  AND  ARSENIC  UPON  CARCINOMA  OF  THE  THYROID. 

The  knowledge  of  the  occasional  effect  of  iodine  as  a  remedy  in  goiter  is  almost  as 
old  as  our  knowledge  of  the  disease  itself.  The  relation  of  iodine  to  the  thyroid  has 
been  the  subject  of  extensive  study  by  modern  chemical  methods  and  by  biological 
experiment.  It  is  well  known  that  the  thyroid  gland  normally  contains  iodine,  and  it 
has  been  contended  that  in  certain  hyperplasias  of  the  thyroid  the  amount  of  iodine 
per  gram  weight  of  thyroid  tissue  is  reduced.  These  facts  have  led  experimenters  to 
hold  that  the  curative  effects  of  iodine  upon  the  hyperplastic  thyroid  is  more  due  to  a 
restoration  of  the  iodine  content  to  a  normal  basis  than  to  the  specific  action  of  iodine 
administered  as  a  remedy.  In  the  mammalian  hyperplastic  thyroid  there  are  fre- 
quently encountered  small  adenomata  which  are  more  or  less  distinct  in  appearance  from 

«  Themeasures  to  be  taken  by  fish  culturists  for  the  prevention  of  thyroid  carcinoma  must  await  a  careful  investigation  planned 
specifically  with  this  end  in  view.  This  we  have  not  been  able  to  undertake.  We  believe,  however,  our  experiments  with 
wild  fish  point  the  way  along  which  efforts  should  be  directed. 

The  matter  of  food  is  undoubtedly  the  most  important  aspect  of  domestication  in  relation  to  thyroid  disease.  The  livers  of 
cattle,  sheep,  and  hogs  are  chiefly  relied  upon  in  rearing  the  salmonoids,  and  the  extent  to  which  this  food  is  varied  or  replaced 
by  heart,  lungs,  horse  flesh,  and  other  animal  proteids  apparently  does  not  alter  the  situation  in  this  respect.  Their  availability 
as  fish  food  makes  it  difficult  to  displace  them,  but  fortunately  they  are  not  inherently  necessary  to  fish  culture.  Vegetable  food 
made  from  staple  grains,  fresh-water  and  marine  fish  and  mussels,  Entomostraca  and  other  Crustacea,  live  maggots  and  even 
living  adult  insects,  have  been  used  more  or  less  as  foods  in  practical  fish  culture.  Most  of  these  are  not  yet  available  in  quan- 
tity, and  none  has  displaced  entirely  the  mammalian  proteids.  Our  feeding  experiments,  however,  indicate  that  such  foods 
would  maintain  normal  thyroid  glands  in  the  sahnonoid  fishes.  To  devise  and  prove  a  composite  ration  properly  balanced  for 
this  purpose  would  seem  a  fish  cultural  problem  worth  while.  Perhaps  a  cooked  mixture  consisting  largely  of  vegetable 
meal  in  which  was  incorporated  fish  flesh  and  a  minor  portion  of  one  of  the  foods  used  commonly  at  present  would  promise 
best.  Possibly  even  small  quantities  of  insects  and  insect  larvae  added  to  this  would  be  an  important  improvement.  Such  a 
food  has  ever  been  a  prime  desideratum  in  fish  culture  and  affords  a  measure  of  protection  against  most  fish  diseases  as  well  as 
against  the  one  now  under  discussion. 

Holding  the  disease  to  be  an  infection,  the  ultimate  problem  is  largely  one  of  prevention,  under  which  would  come  a  more 
stringent  cleanliness  of  fish  troughs  and  ponds,  possibly  the  annual  painting  of  wooden  containers  and  in  the  case  of  dirt  ponds, 
their  occasional  emptying  with  periods  of  sun-drying,  or  a  change  to  cement  construction.  The  selection  and  breeding  of  resistant 
strains,  or  of  resistant  species  like  the  Scotch  sea  trout,  are  obviously  indicated. 

As  for  the  presumption,  which  experiments  indicate,  of  remedial  possibilities  in  the  use  of  mercury  or  iodine,  there  is  no 
sufficient  basis  at  present  for  recommending  their  use  on  a  practical  scale.  This  would  involve  their  administration  over  consid- 
erable periods  of  time  which  their  cumulative  action  might  render  undesirable.  Moreover,  that  they  are  absolute  preventives 
of  the  disease  process  under  discussion  is  not  yet  demonstrated.  The  control  of  this  disease  can  doubtless  be  brought  about  by 
other  means  than  administration  of  chemical  agents.  To  this  end  a  fish-cultural  station  handling  preferably  the  brook  trout 
could  well  be  devoted  to  the  extended  experiments  having  to  do  with  feeding  and  the  access  of  infection  to  the  fish  which  are 
necessary  both  to  more  exact  knowledge  of  the  disease  and  to  its  practical  relations. 


464  BULLETIN   OF  THE   BUREAU   OF   FISHERIES. 

the  surrounding  hyperplastic  tissue  and  have  been  looked  upon  as  developing  from 
embryonic  rests,  especially  rests  of.  the  original  tubular  structure  of  the  fetal  gland. 
From  these  adenomata  the  malignant  neoplasms  of  the  thyroid  are  supposed  to  take 
their  origin. 

Marine  and  Lenhart  (igiob,  p.  20;  191  la,  p.  22),  who  have  extensively  studied  the 
effect  of  iodine  upon  the  mammalian  thyroid,  have  advanced  the  theory  that  hyperplasias 
of  the  thyroid  including  endemic  goiter  are  due  to  insufficiency  of  iodine  in  the  diet  of 
the  individuals  and  that  the  therapeutic  effects  of  iodine  are  the  result  of  restoring  to 
the  thyroid  the  normal  amount  of  iodine.  They  state  that  nodular  struma  or  the  ade- 
nomas found  in  strumous  thyroids  are  unaffected  by  iodine,  and  that  malignant  tumors  are 
unaffected  by  iodine,  and  they  propose  that  the  administration  of  iodine  shall  constitute 
a  biological  test  for  the  purpose  of  distinguishing  between  hyperplasias  which  they  hold 
to  be  due  to  a  physiological  deficiency  of  iodine  and  malignant  tumors  which  they  state 
can  not  be  affected  in  this  way.  The  evidence  of  the  microscope  is  no  longer  to  be  con- 
sidered; the  final  test  is  to  be  whether  or  not  a  given  enlargement  of  the  thyroid  responds 
to  iodine.  It  is  obvious  that  such  a  test  as  Marine  and  Lenhart  have  proposed  is  not 
applicable  to  malignant  tumors  other  than  the  thyroid,  as  it  has  long  been  known  in 
experimental  cancer  research  that  transplantable  mouse  cancer  is  definitely  influenced 
in  its  growth  by  many  chemical  compounds  (Clowes,  1908),  particularly  the  heavy 
metals. 

Schoene  (1910)  showed  that  for  a  time  regression  of  advanced  implanted  mouse 
cancer  could  be  induced  by  the  intraperitoneal  injection  of  iodine  and  mercury  in  the 
form  of  KI  and  HgCl2.  He  found  the  effect  of  mercury  to  be  much  more  marked  than 
that  of  iodine.  It  was  thus  known  that  iodine  had  an  inhibitory  effect  upon  genuine 
neoplasms  and  it  therefore  seemed  possible  that  the  action  of  iodine  upon  the  proliferating 
thyroid  might  be  due  to  some  specific  action  upon  the  tissue,  such  as  these  experiments 
of  Schoene's  indicated  the  agent  possessed  for  genuine  neoplasms  of  other  organs. 
Marine  and  Lenhart  reported  in  1910  that  fish  suffering  with  hyperplasia  of  the  thyroid 
were  favorably  affected  by  adding  iodine  in  the  form  of  Lugol's  solution  to  the  water 
in  the  troughs  in  which  they  were  kept,  and  from  these  observations  applying  the  theory 
above  stated,  concluded  that  the  so-called  carcinoma  of  the  thyroid  in  the  Salmonidae 
was  not  carcinoma  but  simple  hyperplasia,  distinguishable  from  true  neoplasms  by  the 
favorable  effect  of  iodine  upon  the  tissue.  The  remarkable  infiltrative  character  of  these 
neoplasms,  so  well  described  by  Scott,  Plehn,  and  Pick,  and  reported  in  our  first  prelim- 
inary reports,  Marine  explains  as  due  to  the  absence  of  a  capsule.  This  feature  of 
the  case  we  have  dealt  with  under  the  appropriate  heading  and  it  need  not  be  again 
referred  to  here. 

The  results  of  Marine  and  Lenhart  in  causing  regression  or,  as  they  term  it, 
involution  or  reversion,  of  the  hyperplastic  thyroid  in  the  Salmonidae  by  the  administra- 
tion of  iodine  through  the  water,  we  have  been  able  to  confirm.  In  order  to  determine 
whether  the  action  of  the  iodine  was  peculiar  to  this  element  and  might  therefore  be 
looked  upon  as  acting  upon  the  thyroid  by  virtue  of  its  physiological  relation  to  this 
organ,  in  repeating  the  experiments  of  Marine  and  Lenhart  we  decided  to  control  them 


CARCINOMA   OP  THE   THYROID   IN   SALMONOID   FISHES. 


465 


by  treating  under  exactly  the  same  conditions  comparable  fish  with  mercury  in  the 
form  of  HgCl2.  This  gave  the  further  advantage  that  if  mercury  should  prove  to  have 
a  similar  effect  upon  the  thyroid  to  that  determined  by  Marine  and  Lenhart  for  iodine, 
the  relation  of  these  growths  of  the  thyroid  to  one  of  the  heavy  metals  might  be  deter- 
mined, mercury  already  having  been  shown  to  have  an  inhibitory  and  regressive  effect 
upon  genuine  neoplasms.  The  experiments  were  carried  out  in  the  summer  of  1910 
with  the  result,  as  may  be  seen  by  the  accompanying  tables,  that  mercury  was  found 
to  have  an  effect  upon  the  growing  thyroid  of  the  Salmonidae  indistinguishable  from 
that  obtained  with  iodine,  with  the  exception  that  mercury  appeared  to  produce  these 
results  more  certainly  and  more  rapidly  than  did  iodine.  To  further  amplify  the 


FIG.  95.— Floating  siphon.  A  is  the  siphon,  B  the  frame,  and  C  the  container.  The  form  of  the  frame  is  of  course  not 
essential,  and  should  be  adapted  to  the  container.  The  illustrations  show  the  glass  tubing  of  much  larger  size  than  is  neces- 
sary or  practicable  in  small  siphons.  Small  tubing  is  preferable. 

comparison,  during  the  summer  of  1911  experiments  with  arsenic,  an  element  long 
known  to  have  a  favorable  influence  upon  genuine  neoplasms,  were  carried  out,  using 
arsenic  in  the  form  of  As3O5.  These  results  are  also  sufficiently  set  forth  in  the  tables. 

Experiments  were  begun  by  determining  the  toxicity  of  the  iodine  to  trout  when 
added  to  the  water  in  the  form  of  the  pure  element  already  dissolved  in  distilled  water 
and  then  added  to  the  dissolved  potassium  salt.  The  uncombined  iodine  is  much  more 
toxic  than  the  potassium  iodide.  Lake  trout  fry  were  killed  in  less  than  20  hours  by 
one  part  of  free  iodine  added  to  400,000  parts  of  tap  water.  Dilutions  of  i  to  i  ,000,000 
are  safe,  perhaps  because  the  iodine  is  combined  before  it  has  time  to  produce  a  fatal 


466  BULLETIN   OF  THE   BUREAU  OP   FISHERIES. 

result.  At  i  to  600,000  brook  trout  yearlings  were  not  killed  during  three  days,  but 
the  effect  of  iodine  was  seen  in  coagulating  the  slime  on  the  bodies  of  the  fish. 

In  the  form  of  potassium  iodide,  i  part  of  iodine  in  25,000  parts  of  tap  water  killed 
brook  trout  fry  in  two  to  six  hours,  but  i  to  50,000  was  harmless  during  a  trial  of  two 
weeks.  Lake  trout  fry  were  uninjured  by  dilutions  of  i  to  200,000  and  weaker. 

The  administration  of  the  chemical  agents  has  been  accomplished  in  several  different 
ways  and  in  various  dilutions.  The  constant  uniform  dilutions  were  maintained  by 
running  a  solution  of  known  strength  continuously  into  the  fish  troughs  with  the 
measured  water  inflow  at  the  head  of  the  trough,  an  intimate  mixture  being  insured. 
A  barrel  was  used  as  a  receptacle  for  the  solution  and  a  constant  head  for  the  flow  of 
solution  was  maintained  by  the  use  of  a  floating  siphon.  (Fig.  95.)  In  this  way  it 
is  easy  to  keep  the  water  supply  of  the  experiment  constantly  impregnated  to  any 
desired  degree  with  any  soluble  agent. 

The  intermittent  treatments  were  applied  by  adding  single  doses  of  the  chemical 
to  the  water  of  the  fish  trough,  obtaining  fairly  complete  distribution  by  stirring.  Two 
daily  doses  were  given,  and  the  water  supply  was  so  adjusted  as  to  change  the  contents 
of  the  trough  every  four-hour  period.  The  dilution  of  the  chemical  then  proceeded  with 
the  flushing  out  of  the  trough  by  the  water  flow.  The  corners  of  the  trough  may  have 
still  held  appreciable  quantities  of  the  agent  after  the  four-hour  period,  but  the  flow 
must  have  diluted  it  beyond  any  effective  strength  long  before  the  succeeding  portion 
was  added. 

Experiment  i  (table  ix). — Iodine  administered  as  potassium  iodide  and  given  con- 
tinuously under  constant  head  from  a  floating  siphon  into  a  trough  receiving  an  ade- 
quate and  measured  water  supply  direct  from  Craig  Brook  and  having  a  definitely 
known  outflow.  The  water  supply  was  24  liters  per  minute.  The  siphon  flow  of  KI 
solution  was  so  regulated  that  a  constant  concentration  of  iodine  of  i  :  5,000,000  was 
maintained  in  the  flowing  water.  The  temperature  of  the  water  during  the  course  of 
the  experiment  varied  but  little  from  19.5°  C.  The  fish  were  fed  raw  beef  liver.  The 
following  fish  were  subjected  to  this  treatment :  Three  tumored  hybrid  salmon,  6  tumored 
brook  trout,  and  15  clinically  clean  brook  trout.  An  equal  number  of  controls  living 
under  identical  conditions,  with  the  exception  of  the  presence  of  iodine,  were  carried 
through  for  comparative  study.  The  greatest  period  during  which  fish  were  subjected 
to  this  treatment  was  31  days.  Treated  fish  and  controls  were  preserved  for  study, 
however,  at  frequent  intervals  during  the  course  of  the  experiment.  A  brief  statement 
of  results  is  given  in  table  ix.  This  is  self-explanatory.  (Fig.  96,  97,  98,  99,  100,  101.) 

Experiment  2  (table  x). — Similar  in  all  respects  to  experiment  i,  except  for  the 
concentration  of  iodine,  which  was  much  greater,  being  i  :  300,000.  The  fish  were  fed 
raw  beef  liver.  The  fish  subjected  to  the  treatment  were  as  follows:  Four  clinically 
clean  brook  trout,  5  brook  trout  with  pharyngeal  discoloration  (red  floor),  and  6  brook 
trout  with  various  tumors.  Parallel  controls  for  all  these  fish  were  also  studied.  The 
longest  period  of  treatment  in  this  experiment  was  17  days.  Macroscopic  evidence  of 
regression  was  furnished  in  some  of  the  red  floors  and  in  some  of  the  tumor  fish  as 
shown  by  the  disappearance  of  pharyngeal  reddening  and  reduction  of  tumor  measure- 
ment. The  results  of  microscopic  study  of  these  specimens,  together  with  their  controls, 
are  given  in  table  x. 

Experiment  j  (table  xi). — In  this  experiment  iodine  was  administered  intermit- 
tently as  potassium  iodide,  the  greatest  concentration  of  iodine  in  the  water  at  any  one 


CARCINOMA   OF  THE  THYROID   IN  SALMONOID  FISHES.  467 

time  being  i  :  32,000,000  parts.  From  this  strength  dilution  rapidly  occurred,  reaching 
infinity  in  about  four  hours,  the  time  required  for  the  replacement  of  the  water  contents 
of  the  trough  containing  the  fish  experimented  upon.  The  iodine  was  administered 
twice  daily,  morning  and  evening,  so  that  there  were  long  periods  during  which  the  fish 
received  no  iodine.  The  temperature  of  the  water  remained  quite  constant  at  19.5°  C. 
These  fish  were  fed  raw  beef  liver.  The  longest  period  of  administration  was  30  days. 
The  fish  employed  were  15  clinically  clean  brook  trout  yearlings  and  5  small  tumor 
brook  trout  yearlings.  No  special  controls  were  employed  for  this  experiment,  com- 
parisons being  made  with  the  controls  for  the  previous  iodine  experiment.  Here  again 
some  macroscopic  evidence  of  regression  was  furnished  by  diminution  in  size  of  tumors. 
A  brief  resume  of  the  microscopic  study  is  given  in  table  xi. 

Experiment  4. — A  small  number  of  fish  were  tested  for  the  toxicity  of  iodine  admin- 
istered as  Lugol's  solution  into  the  stomach,  and  it  was  found  that  yearling  trout  will 
endure  as  much  as  i  to  5  mg.  and  adult  trout  as  much  as  10  mg.  A  number  of  fish  were 
treated,  some  of  them  during  a  period  of  21  days,  with  injections  into  the  stomach  of 
Lugol's  solution  containing  from  1.16  mg.  to  3.75  mg.  iodine.  Some  of  these  died, 
probably  through  the  cumulative  effect  of  the  iodine.  Definite  reduction  of  tumors 
was  observed.  Microscopic  evidence  of  regression,  although  in  the  main  not  as  marked 
as  that  occurring  in  other  methods  of  treatment,  is  nevertheless  definite. 

Experiment  5,  showing  the  influence  of  mercury  (table  xn).  This  experiment  is 
comparable  with  experiment  i  showing  the  effect  of  iodine  administration.  Mercury 
was  administered  as  HgCl2,  under  constant  flow,  in  a  dilution  of  i  :  5,000,000  of  mercury. 
The  following  fish  were  subjected  to  this  treatment :  Fifteen  clinically  clean  yearling 
brook  trout,  5  brook  trout  showing  red  floors,  and  3  brook  trout  with  tumors.  Parallel 
controls  receiving  no  mercury  were  employed.  Fish  were  killed  and  preserved  at  fre- 
quent intervals,  the  longest  duration  of  treatment  being  30  days.  The  experiment  was 
begun  August  13,  1910.  The  temperature  of  the  water  was  20°  C. ;  feeding,  the  same 
as  for  other  experiments.  Here,  also,  macroscopic  evidence  of  regression  was  furnished 
by  clearing  up  of  red  floors  and  diminution  in  size  of  tumors,  and  in  the  almost  complete 
clinical  disappearance  of  a  tumor  7^  rnm.  in  diameter.  A  brief  summary  of  the  results 
of  microscopic  study  is  given  in  table  xn.  (Fig.  102,  103,  104,  105,  107,  108.)  Three 
days  is  insufficient  to  affect  tumors.  In  one  case,  however,  after  three  days  in 
i  :  5,000,000  the  fish  was  placed  in  i  :  300,000  and  was  killed  by  the  mercury  in  three 
and  one-half  hours.  The  epithelium  showed  great  reduction.  (Fig.  106.)  Another 
after  three  days  in  i  :  5,000,000  and  2.75  mg.  of  HgCl2  introduced  into  the  stomach  on 
the  second  day  showed  no  reduction. 

Experiment  6  (table  xm). — Intermittent  administration  of  mercury  as  HgCl2; 
camparable  to  experiment  3  (intermittent  administration  of  iodine).  Mercuric  chlo- 
ride was  introduced  into  the  water  of  the  trough  containing  the  fish  experimented  upon 
in  such  quantity  as  to  make  a  solution,  for  the  moment,  representing  i  part  of  mercury 
in  38,600,000  parts  of  water.  This  was  done  twice  daily,  at  10  a.  m.  and  4  p.  m.  The 
dilution  was  estimated  to  have  reached  infinity  in  four  hours.  Five  tumored  brook 
trout  and  10  clinically  clean  landlocked  salmon  were  subjected  to  this  treatment  for 
periods  of  15,  31,  and  43  days. 

With  this  high  dilution  of  mercury,  even  at  the  end  of  43  days  there  was  no  definite 
macroscopic  evidence  of  reduction  in  size  of  any  of  the  tumors.  The  histologic  study  of 
the  15  fish  of  this  experiment,  together  with  i  tumor  and  i  clinically  clean  control, 
appear  briefly  summarized  in  table  xm.  Of  the  15  fish  subjected  to  treatment,  5 
show  distinct  evidence  of  regression,  either  in  thyroid  hyperplasia  or  tumor;  2  show 
slight  regression;  2  are  doubtful;  and  3  show  no  evidence  of  change. 


468  BULLETIN   OP  THE  BUREAU   OF   FISHERIES. 

The  results,  therefore,  from  mercury  in  such  high  dilution  and  given  intermittently, 
are  less  marked  than  with  the  high  iodine  dilutions  and  the  less  dilute  mercury  and 
arsenic.  Nevertheless,  as  compared  with  controls,  even  given  in  these  extremely  small 
quantities,  there  is  an  undoubted  effect  from  the  mercury. 

Experiment  7  (table  xiv)  .—Arsenic  administered  in  continuous  flow,  as  As2O5, 
delivered  constantly,  drop  by  drop  from  floating  siphon,  making  a  dilution  equivalent 
to  i  part  of  arsenic  in  300,000  parts  of  water. 

Five  clinically  clean  landlocked  salmon  and  five  tumored  trout  were  subjected  to 
this  treatment.  On  the  fourteenth  day  of  the  experiment  the  following  fish  were  killed 
and  preserved  for  microscopic  examination:  One  with  throat  tumor,  one  with  a  throat 
and  mouth  tumor,  and  two  clinically  clean.  In  addition,  two  controls,  one  tumored 
and  one  clinically  clean,  were  preserved  for  comparison. 

At  the  end  of  the  twenty-second  day  the  experiment  was  discontinued  and  the 
remaining  fish  preserved.  These  consisted  of  three  originally  clean  landlocked  salmon 
and  three  originally  tumored  brook  trout.  Of  the  latter,  there  was  only  one  visible 
tumor  left  and  that  greatly  reduced  in  size.  In  another  a  red  floor  was  the  only  visible 
sign  of  what  was  originally  a  fair  sized  tumor.  (Fig.  109.)  In  a  third  there  was  no 
macroscopic  evidence  of  the  former  tumor. 

Microscopically  all  the  thyroids  of  the  fish  subjected  to  treatment  showed  distinct 
evidence  of  regression.  This  was  most  marked  in  the  fish  in  which  treatment  had  been 
continued  for  22  days.  The  controls,  on  the  other  hand,  had  undergone  no  regression. 
The  results  of  microscopic  study  are  briefly  outlined  in  table  xiv. 

During  the  winter  of  1910,  in  order  to  determine  whether  the  results  obtained  by  the 
administration  of  thymol  in  endemic  goiter  by  McCarrison  could  be  duplicated  by  the 
administration  of  this  drug  through  the  medium  of  the  water  upon  fish  with  carcinoma 
of  the  thyroid,  the  following  experiments  were  carried  out:  Thymol  at  i  part  to  500,000 
of  water,  dissolved  by  the  aid  of  heat  maintained  constantly  in  flowing  water  for  34 
days,  was  without  recognizable  effect  macroscopically  or  microscopically  upon  either 
visible  tumors  or  the  early  stage.  The  temperature  of  the  water  ranged  from  2°  to  3°  C. 
A  brook  trout  yearling  was  killed  between  the  second  and  third  day  by  thymol  at  i  to 
200,000,  indicating  that  solution  of  the  thymol  in  the  water  was  attained. 

Generally  speaking,  iodine,  mercury,  and  arsenic  produce  changes  in  the  prolifer- 
ating thyroid  tissue,  both  in  the  early  and  advanced  stages  of  carcinoma  of  the  thyroid, 
which  are  scarcely  distinguishable  from  the  changes  found  in  spontaneous  recovery. 
In  the  early  stages  the  change  consists  in  a  reversion  of  the  columnar  epithelium  to  the 
flattened  form,  return  of  stainable  colloid,  disappearance  of  hyperemia,  and  the  partial 
disappearance  of  the  most  remote  extensions  of  follicles  in  the  outlying  tissues.  Where 
regression  occurs  rapidly  in  large  tumors  the  first  evidences  of  regression  are  found  in 
extensive  hemorrhages  into  the  substance  of  the  tumor;  in  some  instances  extensive 
areas  of  the  tumor  are  the  seat  of  hemorrhage.  Such  hemorrhages  are  organized  by 
connective  tissue.  (See  fig.  101.)  The  high  columnar  epithelium,  especially  in  the 
peripheral  portions  of  the  tumor,  are  changed  to  flattened  and  atrophic  cells  with 
greatly  diminished  protoplasm.  The  retrograde  changes  are  most  marked  at  the  periph- 
ery, and  the  entire  picture  is  like  that  described  under  spontaneous  recovery,  except 
that  the  process  seems  to  be  more  rapid  and  more  extensive  under  treatment  with 
metals.  The  effect  of  the  metals,  particularly  mercury,  is  found  as  soon  as  the  eighth 


CARCINOMA   OF  THE  THYROID   IN   SALMONOID   FISHES.  469 

day,  and  in  one  instance  where  a  fish  with  a  large  tumor  (fish  1136  of  table  xn,  fig.  108) 
was  subjected  to  mercury  by  immersion  for  three  and  one-half  hours  in  water  containing 
a  much  higher  concentration  than  usual,  by  which  it  was  apparently  poisoned  and 
promptly  died,  the  changes  in  the  tumor  were  comparable  to  results  obtained  only 
by  an  exhibition  of  mercury  at  i : 5,000,000  during  a  period  of  not  less  than  20  days. 

Since  the  experiments  above  referred  to  were  completed,  our  knowledge  of  the  action 
of  the  heavy  metals  upon  carcinoma  in  experimental  animals  has  been  amplified  by  the 
experiments  of  von  Wassermann,  who  has  shown  that  the  intravenous  injection  of 
selenium  in  combination  with  eosin,  when  given  in  large  doses,  is  capable  of  causing  the 
complete  regression  of  large  implanted  mouse  cancers,  followed  by  clinical  cure.  In 
considering  the  results  obtained  by  ourselves  in  carcinoma  of  the  thyroid  in  the  Sal- 
monidae,  showing  the  pronounced  effect  of  iodine,  arsenic,  and  mercury,  it  became 
evident  to  us,  after  the  publication  of  von  Wassermann's  results  obtained  with  selenium, 
that  it  was  highly  probable  that  suitable  compounds  of  any  of  the  heavy  metals  would 
prove  to  have  a  more  or  less  distinctive  effect  upon  neoplasms.  That  this  is  the  case 
is  now  shown  by  the  publication  of  Neuberg,  Caspari,  and  Lohe  (1912)  and  the  results 
obtained  by  the  use  of  colloidal  metals  by  Szecsi  (1912),  and  the  favorable,  although 
temporary  results  obtained  by  the  French  observers  in  the  use  of  colloidal  copper  in 
human  carcinoma. 

All  of  these  experiments,  as  did  the  original  observations  of  Schoene,  dealt  with 
large  doses,  in  many  instances  almost  a  fatal  dose  of  these  metallic  compounds  given 
intravenously.  Lewin  (1913)  has  recently  pointed  out  that  where  immediate  results 
are  obtained  with  metals,  there  is  evidence  of  marked  hemorrhage  into  the  tumor,  and 
believes  that  they  are  able  to  affect  the  tumor  by  their  ability  to  injure  the  capillary 
terminals,  this  explaining  the  hemorrhage.  Although  in  our  experiments  arsenic  and 
mercury  were  used  in  very  great  dilution,  we  have  the  same  evidence  of  hemorrhage 
into  the  tumors,  especially  the  large  ones  that  are  obtained  by  injecting  much  larger 
doses  intravenously  in  animals.  It  seems  highly  probable  that  the  results  obtained 
with  this  great  dilution  are  due  to  a  cumulative  action  of  the  metal.  It  is,  however, 
clear  that  the  results  obtained  in  our  experiments  are  of  the  same  nature  as  those 
obtained  in  neoplasms  of  experimental  animals  by  intravenous  injection.  (Gaylord, 
1912  a.) 

It  seems  assured  that  the  action  of  iodine  upon  the  tumors  of  the  thyroid  in  the 
Salmonidae  is  not  due  to  its  physiological  relation  to  the  thyroid  gland;  that  its  curative 
qualities  are  equally  possessed  by  other  elements,  including  the  heavy  metals,  and  that 
it  acts  by  virtue  of  some  quality  which  it  shares  in  common  with  the  metals;  that  these 
metals  exhibit  the  same  effect  upon  true  neoplasms  in  mammals  and  that  the  effect  of 
iodine  and  metals  upon  the  tumors  of  the  thyroid  in  the  Salmonidae  tends  to  prove  their 
true  neoplastic  nature,  and  that  the  theory  of  Marine  and  Lenhart  that  the  action  of 
iodine  may  be  used  to  distinguish  between  physiological  hyperplasia  and  true  tumor 
formation  is  untenable. 


470 


BULLETIN   OF  THE   BUREAU   OF   FISHERIES. 


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20558;  card  1126. 

oderate  hyperplasia. 
20558;  card  1129. 

ery  positive  regression 
20558;  card  1128. 

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20558;  card  1130. 

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plasia;  controls  for  n< 
Lot  20558  ;  cards  1134^ 
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e  c  i  d  e  d  regression  . 
20558;  cards  1133  A 
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plasia.  Lot  20558; 
1132. 

arked  regression. 
20558;  card  1131. 

Iso  received  2.75  mg.  1 
in  stomach  one  day  h 
death;  no  microscopu 
dence  of  reduction. 
"35- 

days  hi  Hg  i  to  5,00 
then  in  standhlg  Hg 
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tion.  Card  1136;  fig. 

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stomach  2  days  t 
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tion.  Card  1137. 

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marked  histologically 
none  evident  micro 
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isthict  reduction  ma 
in  some  parts  of  tu 
none  hi  others.  Cards 
and  1140. 

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as  no.  27.  Card  1141. 

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Much  less  thyroid,  more  widely  separated, 
larger  follicles. 

Fairly  large  thyroid  mass  of  varying  folli 
soine  very  closely  packed;  others  wi 
separated. 

Much  less  thyroid,  more  uniform;  larger 
widely  separated  follicles. 

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Large  number  of  good-sized  follicles,  s 
loosely  arranged,  others  compact;  very  1 
infiltration  of  muscle. 

Smaller  number  of  larger  follicles  more  loc 
arranged. 

Large  number  of  follicles,  varying  in  size 
shape,  infiltrating  muscle. 

Thyroid  much  smaller;  more  uniformly  1 
follicles. 

Tumors;  pit  and  throat  reduced  i  mm 
diameter;  much  papilliform  epithelial 
vagination. 

A  large  number  of  large  follicles,  more  com 
near  pharyngeal  floor. 

Large  mass  closely  packed  follicles,  n 
epithelial  invagination;  infiltration,  mi 
and  cartilage. 

Tumor  reduced  from  14  mm.  to  18  nur 
diameter,  very  cystic;  large  cysts 
rounded  by  compact  thyroid  contai 
many  small  follicles. 

Tumor  reduced  hi  size;  large  follicles,  n 
irregular  and  with  branching  epithelia 
growths  around  these;  more  compact  sm 
follicles,  others  more  scattered;  foil 
smaller. 

Microscopic  evidence  of  reduction;  extrei 
large  follicles,  surrounded  by  layer  of  sm 
ones;  some  have  ingrowing  epithehal  pi 
he. 

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Epithelium. 

igh,  mostly  cu- 
boidal, some  colum- 
nar; many  follicles 
at  periphery  of  tu- 
mor mass  have  re- 
duced epithelium. 

uch  low  epithelium, 
considerable  desqua- 
mation;  probably 
postmortem  changes. 

ery  low  ;  mostly  com- 
plete reduction,  a 
few  cuboidal. 

ery  low  

ostly  low,  cuboidal; 
a  few  high,  some  co- 
lumnar. 

ostly  very  low;  a  few 
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cuboidal. 

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connective  tis- 
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loose  areolar, 
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connective  tis- 
loose  areolar; 
orrhages,  leuco- 
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connective  tis- 
especially  at  pe- 
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Distribution.  Infiltration. 

mor  reduced  in  size;  many  large  ii 
)llicles,  some  with  papilliform  ingro1 

roat  tumor  which  has  become  s 
losely  packed  follicles  and  some  ep 
lasses;  invasion  of  muscle  and  cartil 

mor  reduced  ^4  mm.;  numerous, 
x>sely  packed,  large  follicles,  mucl 
ing  out  at  periphery  of  mass,  large 
les  in  center  of  mass;  no  evident  i 
ion. 

merous  large  follicles  loosely  packec 
ery  large  like  colloid  cysts. 

mor  little  if  any  reduced  in  size;  gri 
losely  packed  follicles  separated  b 
reolar  and  connective  tissue. 

mm.  tumor  nearly  gone,  consistsin 
irge  and  small  follicles  loosely  an 
thers  more  compact;  tumor  much  t 
ut  at  periphery;  small  atrophied  foil 

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,  sahnon,  clinically  da 
no  marked  evidence  of 
gression;  moderate  hyp 
plasia,  if  anything  ret 
gression.  Lot  1950;  ca 

2O2OA. 

.  sahnon,  clinically  cles 
retrogradulg  hyperplas 
Lot  1950;  card  20208. 

rook  trout;  large  thr( 
tumor;  no  regression;  1 
histologic  appearance 
malignancy.  Lot  aa 
card  202  1  A. 

.  sahnon;  clinically  cles 
control  for  no.  2;  apparc 
regression  of  moderate  1 
perplasia.  Lot  1950;  ca 
2022. 

rook  trout;  pit  turn 
some  regression;  adenon 
mixed  tumor.  Lot  22 
card  2023. 

rook  trout;  tumor,  mot 
and  pit,  in  microsco] 
evidence  of  duninutk 
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2215;  card  20218. 

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retrograding.  Lot  19 
card  2O26A. 

.  salmon,  clinically  cl« 
moderate  hyperplasia; 
trograding.  Lot  1950;  ca 
20268. 

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Pharyngeal  spaces  filled  -with  loosely  packed 
follicles  of  varying  size,  some  very  Jarge  and 
some  very  small,  very  few  of  irregular  out- 
line; some  invasion  of  muscle. 

Isolated  masses  of  mostly  small  follicles  sepa- 
rated from  each  other  by  large  hemorrhagic 
areas;  thinning  out  of  follicles  under  pharyn- 
geal  floor;  some  large  follicles  and  a  few  small 
colloid  cysts;  some  invasion  of  muscle  and 
cartilage. 

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idly packed  columns  and  masses  of  epithe- 
lium with  only  an  occasional  distinct  alve- 
olus in  some  parts  and  scattered  alveoli  in 
others,  widely  separated  by  packed  epithe- 
lium; invasion  of  muscle  and  bone. 

Pharyngeal  spaces  partly  filled  with  typical 
alveoli,  but  varying  greatly  in  size;  no  in- 
vasion of  cartilage  bone  or  muscle;  occa- 
sional small  cyst. 

Mixed  tumor,  in  part  closely  packed  epithelial 
cords;  in  part  adenoma  tous  large  papilhform 
ingrowths  near  surface;  scattered  colloid  con- 
taining alveoh. 

Pharyngeal  spaces  filled  with  spherical  follicles, 
part  of  which  are  small  and  closely  packed  and 
part  large;  many  very  large  and  filled  with 
colloid. 

Relatively  small  masses  of  loosely  packed  fol- 
licles, well  separated,  of  varying  size,  spher- 
ical in  outline. 

Pharyngeal  spaces  moderately  filled  with 
closely  packed  follicles,  some  of  which  are 
very  small. 

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CARCINOMA   OF  THE   THYROID   IN   SALMONOID   PISHES. 


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Distribution.  Infiltration. 

Pharyngeal  spaces  partly  filled  by  follicles  of 
varying  size  and  shape,  some  compact, 
others  loosely  arranged,  many  separating 
spaces  of  areolar  tissue;  apparent  disappear- 
ance of  follicles  under  pharyngeal  floor;  some 
invasion  of  cartilage. 

Layer  under  pharyngeal  floor;  flattened  out 
follicles  between  fibrous  tissue,  which  has 
largely  replaced  the  thyroid  at  this  point;  the 
visible  tumor  portion  is  also  almost  entirely 
replaced  by  connective  tissue;  the  center 
growth  papilliform  in  type,  separated  from 
surrounding  tissue  by  dense  fibrous  tissue 
which  has  apparently  replaced  former 
thyroid. 

Pharyngeal  spaces  filled  with  a  very  variable 
thyroid  mass,  containing  islands  of  papilli- 
form follicles  surrounded  by  typical  follicles 
and  masses  of  new  formed  connective  tissue 
embedding  compressed  follicles;  periphery 
of  tumor  largely  replaced  by  connective 
tissue;  infiltration  of  muscle  and  cartilage. 

Pharyngeal  spaces  partly  filled  by  a  variable 
thyroid  mass;  some  follicles  small  and  closely 
packed  ;  others  large,  separated  by  strands  of 
muscle;  no  invasion  of  cartilage;  not  involv- 
ing floor. 

Rather  widely  separated  and  loosely  arranged 
small  and  large  follicles  scattered  through 
pharyngeal  spaces. 

Islands  of  papilHform  growths  walled  off  by 
large  masses  of  new  formed  connective  tissue 
with  scattered  follicles. 

Pharyngeal  spaces  only  partly  occupied  by 
thyroid  follicles  varying  in  ske  and  arrange- 
ment from  loosely  to  closely  packed  large 
and  small  follicles. 

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BULLETIN   OF   THE   BUREAU   OF   FISHERIES. 


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hyperplasia  moderate, 
definitely  retrograd 
Lot  2081;  card  20348. 

.  sahnon,  clinically  cl« 
moderate  hyperplasia, 
parently  retrograd: 
Lot  2081  ;  card  2039. 

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Lot  2034;  card  2041. 

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5 

Distribution.  Infiltration. 

haryngeal  spaces  filled  with  thyroid  m 
divided  partly  by  connective  tissue  into 
eral  masses  of  somewhat  different  charae 
some  ramifying  papilliform,  others  large, 
small  follicles,  invading  bone  and  muscl 

haryngeal  spaces  only  partly  filled  by  v 
ing  densely  and  loosely  arranged  small 
large  follicles;  some  invasion  of  cartilage 

haryngeal  spaces  partly  filled  with  mor 
less  closely  packed  follicles  of  varymg  i 
invasion  of  muscle;  some  follicles,  ap 
ently  atrophic. 

haryngeal  spaces  partly  filled  with  mor 
less  loosely  packed  follicles,  some  small,  i 
ers  large;  apparent  atrophy  and  thinning 
in  many  places  under  pharyngeal  floor;  t 
roid  tissue  has  largely  disappeared,  isole 
follicles  only  being  included  in  a  dense  n 
of  new-formed  connective  tissue,  part  of 
thyroid  of  the  papilliform  type  shows  cos 
cence  of  follicles  and  a  resumption  of  the  t 
cal  colloid  follicular  arrangement. 

:nter  of  mass  papilliform,  changing  to  col 
containing  follicles;  at  periphery  large  ; 
small  follicles  separated  by  dense  connee 
tissue;  invasion  of  muscle  and  cartilage. 

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5 

CARCINOMA   OF  THE   THYROID   IN   SALMONOID   FISHES.  485 

TRANSMISSION  OF  THYROID  DISEASE  TO  MAMMAUS. 

DOGS. 

In  June,  1910,  a  dog  obtained  in  Buffalo,  and  her  litter  of  six  young,  were  taken  to 
the  Craig  Brook  station  in  Maine.  They  were  placed  in  an  inclosure  near  the  fish  ponds 
and  fed  liver.  They  were  immediately  given  to  drink  constantly  water  from  pond  10, 
and  beginning  with  August  20  a  pan  of  mud  from  the  bottom  of  pond  10  with  pond-io 
water  supernatant  was  supplied  to  them,  the  mud  and  water  kept  constantly  renewed. 
The  animals  not  only  drank  the  supernatant  water  but  consumed  the  mud  in  quantity. 
Seventeen  days  after  the  mud  was  first  placed  at  their  disposal  all  the  puppies  were 
found  to  have  palpable  thyroid  enlargements,  besides  greatly  enlarged  cervical  lymph 
nodes.  This  result  was  briefly  reported  at  the  Second  International  Cancer  Congress  at 
Paris  in  1910. 

The  food  of  the  puppies  was  changed  to  cereal,  and  upon  examination  late  in  Novem- 
ber, 1910,  all  the  enlargements  had  markedly  decreased.  Two  of  the  animals,  dogs  14 
and  15,  were  shipped  to  Buffalo  in  December  and  killed. 

Section  of  the  thyroid  gland  of  dog  14,  under  the  microscope  presents  an  appear- 
ance of  the  tissue  easily  discernible  as  normal.  There  is  some  variation  in  the  size  of  the 
follicles.  The  epithelium  is  flattened,  the  majority  of  the  follicles  filled  with  stainable 
colloid.  There  are  no  evidences  of  hyperemia.  Under  high  power  the  epithelium  is 
uniform  in  size,  flattened,  the  protoplasm  stains  diffusely  with  hematoxylin,  the  nuclei 
stain  deeply,  the  long  axes  in  the  circumference  of  the  lumen.  There  are  no  changes  in 
the  stroma. 

Section  of  the  thyroid  of  dog  1 5  shows  a  remarkable  condition  of  the  tissue.  There 
is  but  the  slightest  suggestion  of  follicular  structure  in  the  section.  (See  fig.  113.) 
The  entire  tissue  is  made  up  of  solid  masses  of  epithelial  cells,  with  deeply  staining 
nuclei.  There  is  absolutely  no  trace  of  colloid  in  any  portion  of  the  section.  Com- 
pared with  dog  14  the  epithelial  cells  and  their  nuclei  are  distinctly  enlarged.  The 
nuclei  stain  deeply.  They  vary  in  size  and  at  some  portions  of  the  section  are  vesicular. 
The  protoplasm  stains  diffusely  with  nuclear  stain  and  is  distinctly  increased  in  amount. 
Under  high  power  the  outlines  of  the  follicles  can  be  traced  by  capillaries.  The  entire 
alveolar  space  is  filled  with  irregularly  shaped  epithelial  cells  lying  somewhat  loosely 
packed  in  some  regions,  more  compactly  in  others.  In  the  more  open  portions  of  the 
section  a  condition  suggesting  papillary  projections  into  the  alveoli  of  the  lumen  may 
be  made  out.  The  nuclei  are  vesicular.  Occasional  karyokinetic  figures  are  found. 
We  have  here  intensive  proliferation  of  the  epithelium,  with  complete  disappearance  of 
the  colloid.  Marked  parenchymatous  struma. 

The  remaining  dogs  of  this  lot  were  later  shipped  to  Buffalo,  and,  at  the  last  exam- 
ination, made  in  July,  1911,  no  palpable  thyroid  enlargement  was  present.  Thyroid 
regression  influenced  by  the  change  from  a  high  animal  protein  to  low  vegetable  protein 
may  be  inferred. 

A  female  brown  spaniel  (dog  24)  obtained  in  Washington,  D.  C.,  was  shipped  to 
the  Craig  Brook  station  in  the  fall  of  1910.  On  November  30  there  was  no  palpable 


486  BULLETIN  OF  THE  BUREAU  OF   FISHERIES. 

thyroid  enlargement.  A  bag  of  pond-io  mud  was  now  placed  in  a  pail,  which  was 
filled  with  Craig  Brook  water  and  placed  in  the  kennel.  The  mud  was  not  renewed, 
but  fresh  water  was  poured  over  it  from  time  to  time.  The  dog  was  fed  a  meat  diet. 
July  5,  1911,  the  right  thyroid  (gland  was  found  enlarged  nearly  to  the  size  of  a  small 
hen  egg.  The  left  gland  was  palpable  but  not  evidently  enlarged.  During  the  next 
year  pond-io  mud  and  water  was  supplied  to  the  dog,  and  on  July  i,  1912,  she  was  in 
good  condition,  with  both  thyroid  lobes  decidedly  enlarged.  The  left  lobe  was  removed 
and  found  to  weigh  19.3  grams,  its  dimensions  being  5.5  by  3.5  by  2.75-centimeters. 
There  was  no  control  for  this  dog. 

Under  the  microscope  the  thyroid  of  dog  24  presents  follicles  of  great  size  filled 
with  stainable  colloid,  protruding  into  which  are  many  bud-like  processes.  The  epi- 
thelium is  columnar  in  the  larger  alveoli,  the  flattened  nuclei  stain  deeply,  are  oval  or 
spherical,  the  protoplasm  also  taking  the  nuclear  stain.  The  bud-like  processes  are 
caused  by  infoldings  of  the  walls  of  the  alveoli  covered  with  columnar  epithelium.  The 
whole  presents  the  appearance  of  a  gland  which  has  been  in  a  state  of  active  hyper- 
plasia,  but  is  at  present  a  colloid  gland. 

The  feeding  of  these  dogs  was  intended  as  a  preliminary  informal  trial  and  was  not 
controlled.  Having  indicated  the  probability  of  positive  results  in  an  important  field, 
more  accurate  experiments  were  begun  with  other  young  dogs. 

A  bitch  with  a  litter  of  five  pups  was  obtained  from  the  District  of  Columbia,  a 
nongoitrous  region.  These  were  shipped  to  the  Craig  Brook  station,  in  October,  1910. 
The  mother  and  two  pups  were  supplied  until  the  following  summer  with  a  pan  of  mud 
from  pond  10  holding  pond-io  water  supernatant,  both  kept  frequently  renewed.  The 
three  remaining  pups  were  held  as  controls  and  received  mud  and  water  from  Craig 
Brook  directly,  unconnected  with  fish-cultural  conditions.  The  food  for  all  was  shredded 
wheat  scrap  and  milk  until  December,  when  it  was  changed  to  dog  biscuit  with  occasional 
cooked  liver,  and  this  continued  until  spring,  when  it  was  again  changed  to  cereal.  The 
two  lots  of  dogs  were  separately  confined  in  kennels  indoors  and  were  exercised  and  let 
loose  only  under  proper  restrictions. 

On  palpation  in  July,  1911,  no  thyroid  enlargement  could  be  detected  in  any  of 
them.  This  experiment  was  now  abandoned  and  a  new  one  instituted  with  scrapings 
from  the  inside  of  unpainted  wooden  fish  troughs  (no.  93),  which  had  long  been  used  to 
hold  domesticated  trout  and  in  which  thyroid  tumors  were  constantly  produced  in  such 
trout.  (Table  in.) 

The  three  pups  formerly  used  as  controls  were  now  given  to  drink  Craig  Brook  water 
from  a  pail  containing  the  fish-trough  scrapings  suspended  in  a  cheesecloth  bag.  The 
material  was  kept  cold  by  standing  it  continuously  in  a  trough  of  flowing  cold  water. 
A  portion  of  the  clear  water  from  the  pail  was  supplied  to  the  dogs  each  day.  The 
mother  and  the  two  pups  which  had  formerly  received  pond-io  mud  and  water  for  several 
months  were  now  used  as  controls  to  the  experiment  with  scrapings.  They  received 
water  taken  from  the  same  pail  and  boiled.  All  the  dogs  were  fed  liver,  cooked  and 
uncooked.  The  experiment  began  August  i,  1911,  and  in  January,  1912,  was  terminated 


CARCINOMA   OP  THE  THYROID  IN  SALMONOID  FISHES.  487 

and  the  dogs  shipped  to  Buffalo.  The  three  which  received  unboiled  water  from  the 
scrapings  were  in  poor  condition  and  one  of  them  died  just  before  shipment. 

Of  these  three  puppies  (dogs  16,17,  and  22)  the  one  which  died  spontaneously  (dog  16) 
and  one  of  the  others  (dog  17),  both  had  plainly  palpable  thyroids,  from  one-third  to 
one-half  larger  than  normal,  in  gross  section,  firm  and  red,  approaching  spherical  instead 
of  normal  fusiform  shape.  In  both  instances  the  two  lobes  were  about  equally  enlarged. 
The  section  of  the  thyroid  of  dog  16  shows  outspoken  evidence  of  hyperplasia.  There 
are  no  spherical  or  oval  follicles,  all  the  open  spaces  in  the  tissue  are  of  irregular  shape 
due  to  pronounced  papillary  projections  of  the  epithelial  structure  into  their  lumina. 
Colloid  is  present  in  some  of  the  follicles.  The  greater  area  of  the  section  is  composed  of 
small  irregularly  shaped  follicles  many  of  which  contain  no  colloid;  others  partly  filled 
with  poorly  stainable  colloid.  Under  high  power  the  epithelium  is  found  to  be  high 
columnar,  the  nuclei  enlarged  and  often  vesicular  with  one  or  more  nucleoli.  There  is 
distinct  enlargement  of  the  capillaries  in  the  stroma.  In  many  areas  the  proliferation 
has  been  so  intense  as  to  practically  fill  the  alveolar  spaces  with  compact  masses  of 
epithelium.  Occasional  deposits  of  brown  hematogenous  pigment  are  found  within 
the  alveoli.  There  is  distinct  variability  in  the  size  of  the  nuclei,  occasional  ones  being 
greatly  enlarged  and  vesicular.  Karyokinetic  figures  are  rare.  Diagnosis:  Marked 
hyperplasia  with  great  reduction  of  colloid.  (Fig.  in,  dog  17.)  The  histological 
description  of  dog  16  applies  in  every  way  to  dog  17.  (Fig.  112.)  Diagnosis:  Marked 
hyperplasia  with  great  reduction  of  colloid. 

Puppy  22  was  not  operated  until  March  18,  when  the  right  thyroid  was  removed. 
It  was  about  normal  in  size,  measuring  35  by  17  by  12  millimeters,  and  weighed  3  grams. 
The  dog  weighed  7.71  kilograms.  The  third  puppy  (dog  22)  presents  a  histological 
condition  in  the  thyroid  similar  to  dogs  16  and  17.  The  epithelium  is  high  columar, 
the  alveoli  of  irregular  shape,  due  to  plentiful  papilliform  processes  into  the  lumen. 
The  larger  alveoli  contain  poorly  staining  colloid.  There  is  some  variation  in  the  differ- 
ent portions  of  the  section  chosen  for  study  in  this  case.  One  portion  somewhat  remote 
from  the  more  intensely  hyperplastic  region  presents  a  somewhat  more  normal  appear- 
ance. The  alveoli  retain  a  more  oval  appearance,  the  papillary  processes  are  smaller. 
More  colloid  is  present.  The  epithelium  is,  however,  high  columnar.  The  nuclei  stain 
poorly  and  more  homogeneously  than  in  the  other  regions  where  they  are  of  a  more 
vesicular  type.  Diagnosis:  Marked  hyperplasia.  (Fig.  115.) 

None  of  the  controls  (mother  and  two  pups,  dogs  19,  20,  and  21)  had  palpable 
thyroid  enlargements.  They  were  all  operated  in  March,  and  the  left  thyroid  of  each 
removed.  These  left  lobes  were  normal  in  size  and  appearance  and  similar  in  size  to  the 
right  lobes.  The  mother  dog  (19)  weighed  10.9  kilograms,  the  left  lobe  2.4  grams;  one 
of  the  pups  (dog  21)  weighed  8.6  kilograms,  its  left  lobe  2.05  grams,  measuring  32  by 
17  by  9  millimeters.  The  other  puppy  (dog  20,  fig.  114)  weighed  10  kilograms;  its  left 
lobe  6.4  grams,  and  measured  47  by  22  by  12  millimeters.  Histological  examination 
of  the  thyroid  of  the  mother  (dog  19)  shows  normal  thyroid  structure  for  a  dog  of  this 
age.  (Fig.  116.) 


488  BULLETIN   OF  THE   BUREAU   OF  FISHERIES. 

The  puppy  (dog  21)  presents  a  thyroid  structure  which  may  be  considered  normal 
for  a  young  dog.  The  alveoli  are  less  spherical  and  oval,  varying  in  size,  filled  with 
stainable  colloid.  The  epithelium  is  flattened.  There  are  some  areas  in  the  thyroid 
structure  in  which  a  slight  tendency  to  budding  of  the  epithelium  with  a  change  to 
columnar  may  be  observed  and  there  are  some  areas  in  which  there  appears  to  be  a 
somewhat  richer  stroma  than  usual.  It  is,  however,  only  an  increase  in  amount  of 
connective  tissue  without  any  evidence  of  changes  in  staining  characteristics  of  the 
cells.  As  this  puppy  received  pond-io  mud  and  water  for  several  months  previous  to 
the  final  experiment,  it  is  possible  that  the  very  slight  changes  here  noted  may  be  evi- 
dence of  the  first  beginnings  of  a  change  induced  during  that  period.  Diagnosis :  Normal 
thyroid  of  puppy.  (Fig.  no.) 

Section  of  the  left  lobe  of  the  thyroid  of  dog  20  shows  follicles  of  varying  size,  the 
oval  and  spherical  type  predominating,  but  some  follicles  in  which  there  is  evidence  of 
beginning  bud  formation.  The  lining  epithelium  of  the  more  simple  follicles  is  flat. 
The  follicles  are  filled  with  stainable  colloid.  In  the  somewhat  more  irregular  follicles 
the  epithelium  forming  the  budlike  projections  into  the  alveoli  is  cubical.  The  nuclei 
are  stained  deeply  and  are  spherical  or  oval.  The  details  of  the  nuclei  can  not  be  made 
out.  Intensely  stained.  There  is  some  slight  thickening  of  the  septa  here  and  there 
through  the  thyroid  tissue.  No  evidence  of  hyperemia,  no  other  change  except  the 
slight  budding.  (Fig.  114.)  The  thyroid  tissue  is  mostly  normal  for  a  young  dog; 
slight  evidences  indicating  the  beginning  of  hyperplasia.  As  this  dog  had  previously 
received  pond-io  mud  and  water,  as  had  dog  21,  slight  evidences  of  hyperplasia  may 
be  due  to  this  previous  stage  of  the  experiment.  Diagnosis:  Areas  of  slight  hyperplasia. 

In  the  same  way  and  beginning  at  the  same  time  (Aug.  i)  as  in  the  preceding  exper- 
iment, a  young  bull  terrier  (dog  18)  was  given  to  drink  water  in  which  was  suspended 
scrapings  from  another  and  old  fish  trough  (no.  9  of  old  hatchery).  The  water, 
however,  was  kept  in  the  kennel  and  the  dog  allowed  to  drink  at  will.  The  tempera- 
ture varied  with  the  weather.  In  the  winter  the  room  was  heated  somewhat  to  prevent 
freezing,  but  seldom  rose  above  45°  F.,  and  was  often  near  the  freezing  point.  The 
control  was  dog  19,  which  received  the  scrapings  water  after  boiling.  Neither  had 
thyroid  enlargement  at  the  beginning  of  the  experiment.  The  food  was  liver  and  dog 
biscuit  for  both.  The  bull  terrier,  after  receiving  for  six  months  water  from  the  pail  in 
which  were  suspended  the  scrapings,  showed  a  marked  emaciation,  muscular  weakness, 
and  a  staggering  gait.  The  thyroid  was  readily  palpable.  The  dog  was  killed  and 
both  lobes  found  distinctly  enlarged,  the  left  lobe  being  about  one-quarter  larger  than 
the  right  and  measuring  54  by  28  by  26  millimeters,  and  both  very  vascular. 

Under  the  microscope  the  thyroid  gland  shows  extensive  pathological  change. 
The  tissue  is  for  the  most  part  made  up  of  a  solid  adenomatous  structure  with  irregular 
and  narrow  spaces  representing  preexisting  vesicles.  Under  low  power  whole  fields  of 
almost  solid  compact  adenomatous  tissue  are  found.  In  the  irregular  clefts  and  spaces 
in  the  more  open  portions  of  the  tissue,  complex  and  marked  papillary  processes  covered 
with  high  columnar  epithelium  characterize  the  tissue.  This  change  may  be  said  to 
be  more  constant  in  the  peripheral  portions  of  the  section  of  the  thyroid  tissue.  (Fig. 


CARCINOMA   OF  THE  THYROID   IN   SALMONOID   FISHES.  489 

1 1 8.)  Passing  toward  the  center  of  the  lobe  there  are  marked  degenerative  processes 
in  the  tissue.  The  clefts  become  fewer  in  number,  the  epithelium  stains  less  irregu- 
larly than  before,  the  irregular  alveolar  openings  are  fewer,  and  the  whole  tissue  is  com- 
posed of  a  confusion  of  cells  with  just  a  suggestion  of  the  previous  clefts  representing 
the  old  alveoli  (fig.  117),  which  in  this  region  appear  to  be  filled  by  desquamated  and 
rather  poorly  staining  cells. 

At  the  very  center  of  the  lobe  the  evidences  of  degeneration  are  more  intense. 
One  finds  masses  of  cell  complexes,  deeply  staining  and  homogeneous  protoplasm. 
The  cell  boundaries  are  destroyed,  the  nuclei,  although  still  staining  deeply,  are  embedded 
in  the  protoplasmic  structure  with  only  the  most  ill-defined  suggestion  of  cell  bounda- 
ries to  the  protoplasm.  (Fig.  119.)  At  the  peripheral  portion  of  the  lobe  where  the 
papillary  adenomatous  type  of  tissue  is  well  preserved,  no  evidences  of  degenera- 
tion are  to  be  found.  One  finds  in  various  places  in  the  capsule  evident  invasion  of 
this  structure.  The  capsule  is  thick,  composed  of  fibrous  connective  tissue  with  small, 
deeply  stained  connective  tissue  nuclei.  In  the  dense  fibrous  structures  of  this  capsule 
at  various  points  definite  alveoli  lined  with  high  columnar  epithelium  are  found,  extend- 
ing in  some  instances  to  the  outermost  limit  of  the  thick  capsule.  Under  high  power 
the  epithelium  of  these  alveoli  and  the  capsule  is  found  to  be  high  columnar,  most  of 
the  nuclei  staining  deeply  and  homogeneously,  but  here  and  there  are  vesicular  nuclei 
with  one  or  more  nucleoli.  The  epithelium  is  in  some  of  these  alveoli  several  layers 
thick;  the  protoplasm  stains  deeply  with  a  cytoplasmic  stain.  Some  of  the  larger  nests 
of  cells  in  the  capsule  have  almost  lost  their  alveolar  structure  and  formed  more  or  less 
compact  islands  of  cells,  with  nuclei  varying  in  size,  many  of  them  vesicular. 

In  the  margins  of  such  a  complex  of  cells  one  finds  direct  invasion  of  the  dense 
connective  tissue  structure  of  the  capsule,  there  being  no  stroma  between  the  vesicles 
and  no  delimiting  membrane  to  them.  In  fact,  individual  cells  can  be  found  invading 
the  connective  tissue  fibers.  Occasional  karyokinetic  figures  are  found  and  about  the 
larger  masses  of  cells  described  there  are  evidences  of  expansive  growth  in  the  arrange- 
ment of  the  immediate  encircling  fibers  of  the  capsular  structure. 

Under  high  power  the  outer  zone  of  adenomatous  proliferation  shows  great  varia- 
bility in  the  nuclei  of  the  cells,  most  of  them  being  vesicular,  with  one  or  two  nucleoli. 
They  vary  in  form  from  elongate  to  oval  and  spherical,  mostly  oval.  The  smaller  nuclei 
stain  more  homogeneously  than  the  larger  ones,  the  epithelium  covering  the  papillary 
projections  is  high  columnar,  the  protoplasm  stains  diffusely,  and  occasional  cells  are 
found  in  this  region  in  which  a  swollen  and  cloudy  appearance  of  the  protoplasm  indi- 
cates the  first  evidence  of  degeneration.  The  stroma  of  the  papillae  is  not  well  devel- 
oped. The  capillaries  are  plentiful  but  do  not  form  a  prominent  part  of  the  picture. 

Approaching  the  center  of  the  lobe,  large  irregular  clefts,  made  up  by  the  papillary 
projections,  are  less  in  evidence  and  large  areas  are  found  in  which  the  epithelium  pre- 
sents peculiar  forms  and  a  swollen,  cloudy  appearance  of  the  protoplasm.  The  cells  are 
of  the  most  bizarre  form  and  shape,  often  are  spindle  shaped,  and  what  has  previously 
been  the  alveolar  spaces  in  the  cells  are  filled  with  closely  packed,  desquamated  epi- 
thelium. The  nuclei  here  still  stain  well,  are  vesicular  in  character,  and  vary  greatly 
8207°— 14 9 


490  BULLETIN   OF  THE  BUREAU  OF  FISHERIES. 

in  size  and  form.  At  the  center  of  the  lobule  where  the  degenerative  changes  are  most 
outspoken  are  found  large  areas  of  desquamated  cells  with  cloudy  protoplasm,  taking 
the  stain  deeply.  The  cell  boundaries  are  not  sharply  defined,  the  nuclei  generally 
smaller  than  in  the  preceding  area,  of  varying  size  and  deeply  stained.  Diagnosis: 
Diffuse  hyperplasia  of  the  thyroid  gland  with  degenerative  changes  at  the  center  and 
invasion  of  the  capsule  at  the  periphery. 

RATS. 

In  1910  and  1911  a  prolonged  attempt  was  made  to  affect  the  thyroid  of  rats  by 
giving  them  water  to  drink  from  the  fish  ponds  in  which  the  disease  was  endemic.  A 
barrel  of  water  from  pond  10  of  the  Craig  Brook  station  and  a  quantity  of  mud  from 
the  same  pond  were  shipped  to  Buffalo  and  kept  in  cold  storage.  A  series  of  experi- 
ments were  begun  with  young  rats  obtained  from  Granby,  Mass.  Each  experimental 
lot  consisted  of  10  rats.  The  food  was  a  mixture  of  corn,  oats,  sunflower  seeds,  and 
dog  biscuit.  The  mud  and  water  was  administered  daily  to  the  separate  lots  as  follows: 

1.  Trout-pond  mud;  small  quantities. 

2.  Trout-pond  mud;  large  quantities. 

3.  Trout-pond  water. 

4.  Craig  Brook  water. 

5.  Trout-pond  mud ;  cooked. 

6.  Trout-pond  water;  boiled. 

7.  Trout-pond  water,  injected  subcutaneously,  followed  by  mud  and  water  feeding. 
The  feeding  of  the  mud,  water,  etc.,  was  continued  with  the  same  individuals  for 

a  period  of  about  six  months.  A  few  were  killed  from  time  to  time  during  this  period 
for  examination  of  the  thyroid.  Neither  in  these  nor  in  those  remaining  at  the  close  of 
the  experiment  were  there  any  thyroid  enlargements  or  any  microscopic  condition  differ- 
ing materially  from  the  controls. 

In  the  light  of  Bircher's  subsequent  observations  there  are  several  reasons  why 
these  experiments  might  have  failed.  Bircher  gives  the  following  reasons  why  water 
may  lose  its  goiter-producing  qualities :  (a)  Water  kept  under  conditions  different  from 
those  of  its  origin  for  days  or  weeks;  (6)  water  which  before  use  has  been  continually 
shaken  or  has  undergone  a  long  trip  by  rail;  (c)  water  to  which  small  amounts  of  chem- 
ical agents  have  been  added ;  (d)  that  the  agent  is  more  active  in  the  water  in  the  sum- 
mer months  and  that  the  source  frequently  loses  its  activity  in  the  winter.^  Three  of 
these  reasons  bear  on  the  possible  negative  nature  of  the  above  experiments,  and  as  they 
are  all  made  with  water  taken  from  ponds  in  which  the  agent  is  present  in  dilute  form, 
it  is  quite  clear  that  the  length  of  time  was  not  sufficiently  great  to  produce  positive 
results.  These  experiments  must  therefore  be  repeated  with  the  animals  at  the  source  of 
water  supply  and  continued  over  a  period  not  less  than  18  months. 

The  pond  water  and  mud  having  failed  to  produce  definite  changes  in  rats  during 
six  months  under  the  experimental  conditions,  a  quantity  of  scrapings  from  one  of  the 
wooden  fish  troughs  (no.  102),  in  which  thyroid  tumors  were  constantly  developed,  was 


CARCINOMA   OP  THE   THYROID   IN   SAI^MONOID   FISHES.  491 

brought  to  Buffalo.  The  material  was  kept  cold  in  a  thermos  bottle  during  transporta- 
tion, and  on  arrival  was  placed  in  a  cheesecloth  bag  and  immersed  in  a  glass  jar  of  water 
and  kept  in  the  refrigerator.  Preliminary  trials  were  made  by  using  this  as  drinking 
water  for  rats  on  a  raw-meat  diet.  No  marked  changes  occurred  during  the  first  month, 
but  at  four  months  one  of  six  rats  showed  a  great  enlargement  of  the  thyroid,  and  nearly 
all  had  marked  pathological  changes  consisting  of  reduction  of  colloid,  increase  in  height 
of  epithelium,  congestion  and  presence  of  numerous  mitoses.  A  carefully  controlled 
experiment  was  now  begun  with  the  scrapings  water,  the  diet  being  changed  to  dog  bis- 
cuit and  salted  lake  herrings,  the  latter  for  the  purpose  of  increasing  thirst  and  con- 
sumption of  the  water.  Twenty-four  rats  received  the  scrapings  water,  and  12  control 
rats  received  boiled  water  from  the  same  source.  This  experiment  is  still  in  progress. 
The  results  at  the  close  of  this  record  indicate  that  the  rat  thyroids  undergo  changes 
similar  to  those  in  the  dogs,  but  of  a  less  intensive  nature.  Figure  120  shows  a  normal 
thyroid  of  the  rat  from  a  control;  figure  121,  hypoplastic  thyroid  from  a  rat  from  this 
experiment. 

In  considering  the  above  experiments,  from  which  it  will  be  seen  that  a  definite 
enlargement  with  diffuse  proliferation  of  the  thyroid  gland  may  be  produced  in  dogs 
in  a  period  of  five  months  by  giving  them  to  drink  the  water  in  which  suspended  scrap- 
ings from  wooden  troughs  in  which  the  fish  kept  had  regularly  developed  carcinoma  of 
the  thyroid,  and  that  the  control  dogs  receiving  the  same  water  boiled  have  in  the  same 
time  developed  no  appreciable  change  in  the  thyroid  gland,  it  naturally  becomes  impor- 
tant to  determine  what  is  the  exact  character  of  the  change  in  the  thyroid  gland  of  the 
experimental  dogs. 

At  the  time,  1910,  when  the  first  experiments  along  these  lines  were  made,  we 
were  not  aware  of  the  experiments  of  Bircher  and  of  Wilms  in  the  production  of 
goiter  in  dogs  and  rats  by  giving  them  water  to  drink  from  goitrous  wells.  From  the 
various  publications  of  E.  Bircher  it  will  be  seen  that  in  his  results  obtained  in  rats 
(1911,  b)  he  has  produced,  in  periods  varying  from  9  to  18  months,  distinct  enlargement 
of  the  thyroid,  with  pathological  changes  which  he  divides  into  two  classes,  viz,  nodular 
or  adenomatous  type  and  parenchymatous  hyperplastic,  mostly  with  degenerative 
processes.  In  the  nodular  hyperplastic  form  he  has  produced  typical  struma  nodosa, 
which,  as  he  points  out,  is  a  condition  of  the  mammalian  thyroid  intimately  associated 
with  tumor  formation.  The  parenchymatous  hyperplastic  type  seems  to  be  an  expres- 
sion of  a  more  intensive  action  of  the  goiter  water,  and  it  is  to  this  type  that  the  changes 
we  have  produced  in  the  thyroids  of  our  experimental  dogs  more  closely  approximate. 
In  dog  1 8,  in  which  we  have  the  most  outspoken  change,  we  find  distinctly  marked  degen- 
erative changes  of  the  protoplasm  in  the  center  of  the  lobe.  These  changes  give,  at 
first  glance,  the  impression  of  being  due  to  poor  fixation  of  the  tissue  or  to  post-mortem 
change. 

Changes  of  a  similar  nature  have  been  produced  by  de  Quervam  (1904)  in  the  thyroid 
by  the  injections  of  toxic  substances.  De  Quervain's  studies  indicate  that  the  process 
is  intravital,  and  for  his  tumor  rats  Bircher  takes  the  same  position.  It  is  of  great 
interest  that  Halsted,  who  originally  (Welch,  1888)  showed  that  by  removing  a  part  of 


492  BULLETIN   OF  THE  BUREAU  OF  FISHERIES. 

the  thyroid  of  normal  dogs,  the  remaining  portion  would  become  hyperplastic  (1896), 
has  recently  (1913)  repeated  these  experiments  and  now  finds  that  when  the  present-day 
aseptic  methods  are  employed,  especially  the  careful  sterilization  of  the  skin  with  iodine, 
no  compensatory  hypertrophy  results.  Although  not  definitely  expressing  himself  as  to 
the  cause  of  the  hyperplasia  which  followed  his  original  experiments,  in  the  light  of  de 
Quervain's  production  of  hyperplasia  with  the  products  of  organisms,  above  referred  to, 
Halsted  recognizes  the  possibility  that  the  hyperplasia  in  the  older  experiments  may 
have  been  due  to  infection. 

The  experiments  of  Bircher  indicate  a  very  intimate  relation  between  the  experi- 
mental production  of  struma  in  rats  and  dogs  and  the  etiology  of  tumors  of  the  thyroid. 
The  fact  that  he  has  produced  nodular  struma  in  rats,  that  struma  nodosa  is  generally 
looked  upon  as  the  change  from  wilich  neoplasms  of  the  thyroid  in  mammals  spring,  that 
the  other  changes  of  the  thyroid  in  his  experimental  rats  present  intensive  parenchyma- 
tous  hyperplastic  degeneration,  makes  it  clear  that  perhaps  the  concentration  of  the 
agent  causing  goiter  and  the  method  of  its  administration,  the  length  of  time  in  which 
it  is  permitted  to  work,  or  the  intensity  of  its  action  may  determine  the  character  of  the 
early  changes  of  the  thyroid  in  these  experiments.  The  changes  in  our  dogs  have  appar- 
ently developed  more  quickly  and  more  intensely  than  those  in  the  experiments  made  by 
Bircher.  This  would  probably  explain  why  our  results  have  shown  such  diffuse  and 
intensive  changes  in  the  thyroids  of  our  affected  dogs.  Dog  18,  the  only  adult  dog  so  far 
exposed  to  the  action  of  the  agent  in  our  experiments,  presents  outspoken  degenerative 
changes  at  the  center  of  the  gland  and  evidences  of  infiltration  of  the  capsule.  The 
period  of  time  covered  by  Bircher's  experiments  was  much  longer  than  those  of  our  own. 

We  have  reported  briefly  on  a  few  experiments  with  rats,  from  which  it  is  clear  that 
hyperplastic  changes  in  the  thyroid  may  be  induced  in  rats  under  conditions  similar 
to  those  detailed  in  the  experiments  with  the  dogs.  There  are  many  other  points  of 
similarity  between  Bircher's  experiments  and  ours.  The  agent  is  in  both  cases  destroyed 
by  boiling  and  it  is  not  readily  transported  for  a  great  distance.  We  have  been  unable 
to  produce  changes  in  the  thyroid  of  rats  with  water  transported  from  Maine  to  the 
institute  in  Buffalo.  Our  prompt  and  best  results  have,  as  with  Bircher,  been  obtained 
by  giving  the  water  from  the  scrapings  freshly  to  the  animals  on  the  ground  where  the 
agent  is  produced.  We  have  not  yet  been  able  to  carry  out  extensive  filtration  experi- 
ments, but  have  such  experiments  in  progress  and  hope  to  report  on  them  later. 

Bircher,  in  his  experiments,  has  compared  the  results  obtained  in  the  production  of 
experimental  struma  in  rats  with  the  results  obtained  by  de  Quervain  and  argues  there- 
from that  the  agent  of  goiter  as  he  finds  it  in  Switzerland  is  probably  a  parasitic  agent. 
He  finds  in  filtration  experiments  with  moderately  fine  Berkefeld  bougies  that  intensive 
general  degenerative  changes  of  the  nature  of  cretinism  are  produced  by  the  residues 
scraped  from  the  outside  of  the  filters,  and  infers  that  possibly  it  is  the  toxic  products  of 
an  organism  which  pass  through  the  filter.  These  toxic  products  tend  to  produce  struma 
and  the  unfilterable  portions  possibly  contain  the  organism  that  tends  to  produce 
general  constitutional  disturbances  of  growth,  i.  e.,  cretinism.  Our  dog  18  showed 
general  nutritional  disturbances,  loss  of  weight  and  strength,  staggering  gait.  To  deter- 


CARCINOMA   OP  THE  THYROID   IN  SAI^MONOID   FISHES.  493 

mine  whether  or  not  extensive  constitutional  disturbances  can  be  produced  with  the 
agent  which  we  hold  responsible  for  carcinoma  of  the  thyroid  in  fish  will  require  extensive 
experiments  with  young  animals  carried  over  a  longer  period  of  time  than  our  experi- 
ments have  thus  far  encompassed.  It  is  quite  clear  from  these  experiments  that  there  is 
a  most  intimate  relation  between  the  experimental  production  of  goiter  and  the  develop- 
ment of  malignant  disease  of  the  thyroid  in  mammals.  The  infiltration  of  the  capsule 
in  dog  1 8  is  extremely  suggestive.  Further  experiments  with  older  animals  carried  over 
a  considerable  period  of  time  will  be  necessary  before  it  can  be  definitely  determined 
whether  or  not  the  agent  responsible  for  carcinoma  of  the  thyroid  in  trout  is  capable  of 
producing  infiltrating,  possibly  metastasising  tumors  in  mammals.  Bircher's  experi- 
ments in  producing  nodular  struma  in  rats  makes  the  outlook  in  this  direction  promising. 

The  first  attempts  to  produce  experimental  goiter  in  the  lower  animals  by  giving 
them  to  drink  water  from  goitrous  sources  were  undertaken  by  Klebs  and  H.  Bircher 
(1883?)  who,  however,  did  not  arrive  at  successful  results.  Carle  in  1888  and  Lustig 
in  1890  succeeded  in  producing  in  both  dogs  and  horses,  in  regions  free  from  goiter, 
enlargement  of  the  thyroid  as  the  result  of  giving  them  water  from  goitrous  sources 
over  a  period  of  months.  The  most  elaborate  and  carefully  studied  experiments  are 
those  by  H.  Bircher,  jr.,  above  referred  to.  Since  his  observations  R£pin  (1911)  and 
Breitner  (1912)  have  carried  out  experiments  and  confirmed  his  results  especially  in 
rats,  dogs,  and  monkeys,  their  experiments  likewise  extending  over  several  months. 

Dieterle,  Hirschfeld,  and  Klinger  (1913)  have  repeated  the  experiments  of  Bircher, 
Wilms,  Re"pin,  and  others,  and  arrive  at  the  following  conclusions:  That  in  regions  in 
which  goiter  is  endemic  it  is  possible  to  produce  goiter  in  rats  by  giving  them  copious 
amounts  of  water  to  drink.  Their  success  ranges  from  40  to  70  per  cent.  Second,  the 
nature  of  the  water  which  is  used  in  a  goitrous  locality  is  without  significance.  The 
water  may  be  either  fresh  or  boiled,  and  goiter  may  be  produced  with  water  which  at 
the  point  of  its  origin  is  not  a  goiter-producing  water.  Rats  in  a  goiter-free  locality 
in  Zurich  which  were  given  goiter  water  from  other  localities  did  not  at  first  develop 
goiter.  Later,  however,  a  few  positive  results  were  obtained,  but  it  was  felt  that  con- 
tact infection  could  not  be  excluded.  Because  it  is  possible  to  develop  goiter  in  rats 
in  goiter  regions  with  water  from  goiter-free  localities,  they  conclude  that  the  primary 
character  of  the  water  is  not  the  determining  factor  in  the  development  of  goiter. 
They  point  out  that  in  goiter  localities  boiling  the  water  does  not  protect  experimental 
animals  against  the  development  of  goiter,  but  that  in  goiter-free  localities  boiling  the 
water  destroys  the  goiter-producing  character  of  such  water.  They  conclude  that  this 
indicates  that  the  etiologic  agent  of  goiter  must  be  occasionally  transmitted  through 
the  water.  These  experiments  conform  with  the  work,  as  yet  unpublished,  of  Land- 
steiner,  Schlagenhaufer  and  Wagner,  and  v.  Jauregg,  which  will  show  that  rats  which 
were  given  nothing  but  boiled  water  from  Vienna  and  kept  in  a  peasant's  house  in  the 
neighborhood  of  Rothenthurm  in  Judenburg,  in  Steiermark,  in  which  all  the  inmates 
of  the  house  were  either  goitrous  or  cretinic,  developed  goiter  in  a  percentage  equal  to 
that  obtained  with  rats,  using  the  goitrous  water  of  that  locality,  whereas  attempts  to 
produce  goiter  in  rats  in  Vienna  with  the  goiter  water  of  Rothenthurm  gave  only  nega- 
tive results. 


494  BULLETIN   OF  THE   BUREAU   OF  FISHERIES. 

It  would  thus  appear  that  water  is  not  the  exclusive  carrier  of  the  etiological  agent 
of  goiter,  but  the  giving  of  large  quantities  of  water  to  experimental  animals  in  a  goi- 
trous region,  favors  the  development  of  goiter  when  the  agent  may  find  entry  in  some 
other  way.  These  observations  tend  to  increase  the  significance  of  the  finding  of  nema- 
todes  or  other  possible  carriers  in  connection  with  the  production  of  experimental 
goiter  in  animals. 

McCarrison  (1909)  produced  experimental  goiter  in  human  beings  by  giving  them 
residues  from  the  filtered  water  of  Kashrote,  where  goiter  prevails  to  the  extent  of 
45  per  cent  of  the  total  population.  Experiments  were  carried  out  in  the  nongoitrous 
village  of  Barmis  so  controlled  that  they  were  provided  with  water  for  drinking,  bathing, 
and  other  cleansing  purposes  from  the  Barmis  spring,  which  is  nongoiter  producing, 
but  which,  as  an  added  precaution,  was  boiled.  Their  diet  was  chiefly  vegetable.  Of  13 
individuals  who  consumed  the  untreated  residue  of  the  goiter-producing  water  of  Kashrote 
4  developed  a  noticeable  swelling  of  the  thyroid  gland,  while  2  others  showed  an  increase 
in  size  of  the  organ,  demonstrable  by  measurement  and  evident  to  the  touch.  In  three 
cases  the  enlargement  was  produced  early,  making  its  appearance  on  the  thirteenth  to  the 
fourteenth  day  of  the  experiment.  It  was  not  great  nor  did  it  appear  under  the 
conditions  of  the  experiment  to  be  progressive.  Of  eight  individuals  who  under  the 
same  conditions  consumed  the  boiled  residue  of  the  goiter-producing  water  of  Kashrote 
none  developed  any  swelling  of  the  thyroid  gland,  and  this  although  three  were 
individuals  peculiarly  likely  to  respond  to  goitrous  influences.  McCarrison  therefore 
concluded  (i)  that  goiter  is  due  to  matter  in  suspension  in  the  water;  (2)  that  goiter 
is  not  due  to  the  mineral  but  to  the  living  part  of  the  suspended  matter;  in  other  words, 
to  a  living  organism  of  the  disease;  (3)  that  the  incubation  period  of  experimentally 
produced  goiter  is  13  to  15  days. 

An  experiment  of  similar  import  is  reported  by  Breitner  (1912)  which  relates  to  a 
family  of  father,  mother,  and  seven  children  who,  coming  from  a  goiter-free  region, 
drank  the  water  from  a  goitrous  well  with  the  result  that  all  nine  individuals  developed 
a  great  increase  in  the  circumference  of  the  neck  with  palpable  tumors.  Upon  the 
advice  of  Breitner  they  boiled  the  water  from  this  source  and  after  a  period  of  four  weeks 
a  distinct  diminution  of  the  thyroid  tumors  occurred,  but  later  they  disregarded  this 
advice  with  the  result  that  the  thyroid  enlargement  again  progressed.  From  this  well 
Breitner  carried  out  experiments  with  rats  with  the  result  that  in  19  rats  2  developed 
large  visible  struma,  2  thyroids  two  and  one-half  times  as  large  as  normal,  arid  4  showed 
microscopic  diffuse  enlargement  of  the  thyroid,  whereas  20  controls  showed  no 
enlargement. 

The  literature  contains  many  accounts  of  human  beings  going  from  nongoitrous 
regions  into  localities  in  which  goiter  is  endemic  and  there  quickly  acquiring  the  disease. 
One  of  the  oldest  and  most  striking  of  those  given  is  that  reported  by  Hancke  in  1819, 
in  which  all  but  70  young  men  of  a  battalion  of  300  in  the  course  of  a  year  developed 
such  pronounced  goiter  that  it  was  found  necessary  to  remove  the  regiment  to  a  non- 
goitrous  region,  where  those  who  were  not  too  far  advanced  recovered,  the  enlargement 
of  the  thyroid  disappearing.  Hancke  states  that  in  the  infected  region  referred  to 


CARCINOMA   OP  THE  THYROID  IN   SALMONOID   FISHES.  495 

individuals  who  boiled  the  water  and  freed  it  from  the  precipitate  which  it  contained 
and  added  thereto  wine  and  sugar  very  rarely  developed  goiter.  Another  striking 
example  of  the  same  kind  is  that  of  McClelland  (1835)  relative  to  an  endemic  of  goiter 
in  Deoba,  India.  In  this  locality  the  entire  population  with  the  exception  of  the 
Brahmins  had  goiter.  This  higher  caste  drew  their  drinking  water  from  a  widely  distant 
spring.  One  or  two  other  castes  which  had  partial  access  to  this  source  numbered  a 
considerable  percentage  of  goiter  cases,  and  the  lowest  caste,  the  Domes,  drew  their 
entire  water  supply  from  a  goitrous  well  and  almost  every  individual  had  goiter.  The 
middle  caste,  Ragpoots,  which  received  partly  good  and  partly  infected  water  from  the 
well  were  infected  to  the  extent  of  two-thirds  of  the  individuals.  These  examples  are 
but  one  or  two  from  many  in  the  literature.  Those  who  desire  to  multiply  such  reports 
are  referred  to  Hirsch's  Handbuch  der  historisch-geographischen  Pathologic  (2.  Stuttgart 
1883,  bd.  2,  p.  83),  and  Ewald's  excellent  work  on  Die  Erkrankungen  der  Schilddriise, 
Myxodem  und  Kretinismus,  in  Nothnagel's  Handbuch  der  speziellen  Pathologie  und 
Therapie  (2.  aufl.,  Wien  1909,  bd.  22). 

It  is  clear  both  from  recorded  incidence  in  man  and  from  experiments  both 
with  man  and  animals  that  goiter  is  usually  acquired  through  the  drinking  water.  It 
has  been  shown  that  from  the  water  sources  from  which  man  acquires  goiter,  dogs  and 
rats  may  be  made  to  develop  it.  We  have  shown  that  with  water  in  which  fish  develop 
carcinoma  of  the  thyroid,  diffuse  parenchymatous  enlargement  of  the  thyroid  in  both 
dogs  and  rats  may  be  produced.  From  these  facts  inferences  may  be  drawn  that  there 
is  every  reason  to  believe  that  human  beings  also  would  acquire  thyroid  disease  from 
the  use  of  such  water. 

POSSIBLE  CARRIERS. 

In  a  disease  like  carcinoma  of  the  thyroid  in  the  Salmonidae,  which  is  not  trans- 
mitted directly  from  individual  to  individual  but  which  is  transmitted,  if  at  all,  from 
the  infected  to  the  healthy  by  some  roundabout  method,  the  idea  of  carriers  for  the 
agent  which  we  believe  to  be  the  cause  of  the  disease  is  very  natural.  Of  the  recent 
experimenters  with  goiter  water,  Bircher,  as  a  result  of  filtration  experiments,  for 
some  time  advocated  the  view  that  the  agent  of  goiter  was  a  colloidal  toxin,  probably 
liberated  by  some  parasite  incapable  of  passing  the  Berkefeld  filter.  The  residues 
scraped  from  such  filters  produced  in  young  animals  very  profound  nutritional  changes 
comparable  to  cretinism.  The  filterable  factor  which  produces  the  nodular  adenoma - 
tous  form  of  goiter,  as  well  as  the  parenchymatous  hyperplastic,  will  not  pass  through 
the  membrane  of  a  dialyzer,  but  the  residue  upon  the  dialyzer  membrane  proved  to  be 
particularly  active.  These  observations  have  led  Bircher  to  the  belief  that  the  agent 
is  a  colloid,  but  he  recognizes  that  it  may  also  be  a  filterable  microorganism;  or  that 
if  the  organism  itself  does  not  pass  the  filter  it  is  still  the  probable  source  of  a  filterable 
toxin. 

Many  authors  have  held  that  endemic  goiter  is  certainly  an  infectious  disease, 
Ewald  being  one  of  the  strongest  advocates  of  this  theory,  and  McCarrison  holds  the 
same  view.  Schittenhelm  and  Weichardt  (1912)  consider  it  an  infectious  disease  and 


496  BULLETIN  OF  THE  BUREAU  OF  FISHERIES. 

state  that  by  immunizing  rabbits  with  goiter  water  which  was  free  from  all  bacteria 
or  other  cultivable  organisms,  they  have  gotten  with  the  blood  of  such  immunized 
rabbits  a  definite  deviation  of  the  complement  reaction,  as  against  the  suppositions 
organism  in  the  water.  By  means  of  the  epiphanin  reaction  they  believe  they  have 
demonstrated  the  existence  of  an  antibody  opposed  to  microorganismal  albumin. 

Kolle  (1909)  attempted  to  test  the  theory  that  intestinal  parasites  bore  a  relation 
to  endemic  goiter.  McCarrison  (1909)  was  of  the  opinion  that  the  agent  of  goiter  was  in 
the  intestinal  tract,  because  of  the  prompt  results  obtained  in  his  experience  by  the  giv- 
ing of  a  single  or  repeated  doses  of  thymol.  He  (1911)  tested  this  hypothesis  experi- 
mentally by  mixing  the  feces  of  goitrous  men  with  sterilized  soil  and  he  fouled  water 
with  this  mixture  by  pouring  it  through  a  specially  constructed  box.  In  one  of  these 
boxes  he  placed  500  earthworms  on  the  assumption  that  they  might  be  an  intermediary 
host  of  the  infecting  agent.  Water  from  the  first  box  was  given  to  six  female  goats  and 
from  the  second  with  the  earthworms  to  seven  female  goats.  These  goats  were  permit- 
ted to  consume  this  highly  polluted  water  for  64  days  with  the  following  results:  First, 
loss  of  weight  due  doubtless  to  confinement  in  a  small  hut  for  the  64  days  of  the  experi- 
ment; second,  many  of  them  suffered  from  diarrhea;  third,  50  per  cent  of  the  animals 
showed  marked  enlargement  of  the  thyroid  gland,  most  marked  on  the  right  side. 
The  thyroids  of  three  goats  showed  no  enlargement.  The  enlargements  were  of  various 
degree.  McCarrison  gives  the  average  weight  of  the  normal  thyroid  of  the  goat  of 
Gilgat  as  10000"  of  the  body  weight.  The  enlarged  gland  of  the  goats  in  the  experiment 
weighed  from  ^gVg  t°  7  0*0  o  part  of  the  body  weight.  In  both  batches  receiving  the 
fouled  water  the  results  observed  were  the  same. 

Microscopical  examination  of  the  enlarged  organs  by  McCarrison  showed  "various 
degrees  of  dilatations  of  the  vesicles  and  no  alterations  in  the  connective  tissue  stroma 
of  the  enlarged  glands.  The  hypertrophy  was  due  wholly  to  the  distension  of  the 
vesicles  with  colloid  and  to  the  formation  of  new  vesicles  from  intravesicular  masses 
of  cells."  He  concludes:  (i)  An  hypertrophy  of  the  thyroid  gland  of  goats  may  be 
induced  by  infecting  the  water  supply  with  feces  from  sufferers  from  goiter.  It  is  at 
present  impossible  to  state  whether  this  hypertrophy  is  due  to  the  action  of  the  infect- 
ing agent  of  goiter  or  only  to  the  organic  impurity  of  the  water  thus  contaminated. 
(2)  Earthworms  do  not  appear  to  be  concerned  in  the  spread  of  goiter.  (3)  The  micro- 
scopic appearances  described  are  the  earliest  changes  in  the  formation  of  parenchyma- 
tous  goiter. 

.  One  of  the  most  interesting  recent  discoveries  in  relation  to  a  parasitic  thyroiditis 
is  found  in  the  publication  of  Carlos  Chagas  (1911).  This  author,  cited  by  Schitten- 
helm  and  Weichardt,  found  in  an  insect,  a  Brazilian  bedbug  (barbeiro,  Conochinus 
megistus],  a  flagellate  which  he  identified  as  part  of  the  developmental  cycle  of  Try- 
panosoma  minasense  Chagas,  which  he  had  discovered  in  the  silky  monkey.  If  the 
infected  bedbugs  were  allowed  to  bite  this  variety  of  monkey  the  latter  received  a  blood 
infection  with  the  organism.  The  bedbug  is  therefore  the  intermediary  host  and  the 
incubation  period  after  the  bite  is  eight  days.  Chagas  undertook  to  determine  the 
original  host  for  this  organism  and  found  in  the  State  of  Minas  Geraes,  especially  in 


CARCINOMA  OF  THE   THYROID  IN   SALMONOID   FISHES.  497 

children,  a  flagellate  disease  which,  when  the  patient  was  transferred  to  Rio  Janeiro, 
he  was  able  to  transfer  to  the  silky  monkey  by  means  of  the  barbeiro.  The  charac- 
teristic symptoms  of  the  disease  in  the  children  were  enlargement  of  the  thyroid,  the 
stupefied  appearance  of  the  child,  and  enlargement  of  the  lympahtic  glands.  He  also 
succeeded  in  inoculating  guinea  pigs  with  the  flagellate  organism  by  injecting  the  blood 
of  the  infected  children. 

He  divided  the  disease  into  an  acute  and  a  chronic  form.  The  chronic  form  is  char- 
acterized by  hypertrophy  of  the  thyroid  affecting  one  or  both  of  the  lobes  of  the  thyroid 
and  frequently  the  isthmus.  Even  in  young  children  the  enlargement  of  the  thyroid 
may  be  very  marked.  He  says  that  in  some  regions  the  disease  is  very  widespread  and 
here  infantilism  and  cretinism  are  very  prevalent.  All  these  individuals  presented  the 
characteristic  enlargement  of  the  thyroid.  The  histologic  picture  of  the  disease  is  in 
part  an  inflammatory  reaction  of  the  stroma  of  the  thyroid  with  outspoken  sclerosis. 
In  such  cases  the  alveoli  are  small  and  the  lumen  reduced.  The  colloid  is  usually 
decreased  in  amount  and  stains  poorly.  In  the  vesicles  there  appears  to  be  desquama- 
tion  and  degenerative  changes  of  the  epithelium  which  fill  the  lumina  of  the  alveoli. 
The  islands  of  epithelium  which  normally  lie  between  the  vesicles  appear  to  have  been 
increased  by  proliferation,  in  some  covering  extensive  areas.  Large  cysts  filled  with 
colloid  characterize  the  last  stages  of  the  chronic  form,  with  occasional  calcification  of 
the  cyst  wall. 

In  cancer  of  various  kinds  intermediary  carriers  have  been  suspected.  The  well- 
known  association  of  cancer  in  Bilharzia  disease  with  the  important  trematode  parasite, 
Distomum  haematobium,  is  classic.  Borrel  in  1 906  reported  having  found  very  frequently 
in  mouse  cancer,  in  the  immediate  neighborhood  of  or  within  the  tumor,  occasional 
small  nematode  worms.  These,  he  did  not  think,  were  themselves  in  etiologic  relation 
to  the  tumors,  other  than  as  possible  carriers  of  a  specific  virus.  This  theory  was 
strengthened  in  his  mind  by  finding  in  the  left  kidney  of  a  rat,  which  died  of  a  cancerous 
tumor  in  the  right  kidney,  a  small  cyst  containing  a  very  young  cysticercus,  which  was 
identified  as  belonging  to  the  Tsenia  crassicola  of  the  cat.  Upon  the  membrane  of  this 
cyst,  which  was  attached  to  the  tissue  of  the  kidney,  he  found  a  small  tumor  of  identical 
structure  to  that  of  the  larger  tumor  of  the  right  kidney. 

In  the  second  case,  furnished  him  by  Laveran,  a  rat  died  of  a  tumor  of  the  liver 
of  the  size  of  an  orange,  in  the  exact  center  of  which  was  found  a  cyst  with  a  tumor 
growing  out  from  it  in  all  directions.  This  cyst  contained  a  cysticercus  which  was 
again  identified  as  belonging  to  the  Tsenia  crassicola  of  the  cat.  Microscopically  this 
tumor  was  a  large-celled  sarcoma.  Bipolar  and  multipolar  karyokinetic  figures  were 
very  numerous.  This  tumor  proved  to  be  transplantable  and  had  produced  large 
tumors  for  three  or  more  generations.  Borrel  felt  that  the  successful  transplantation  of 
this  tumor  strongly  indicated  that  the  cysticercus  had  carried  with  it  a  virus  which  it  was 
possible  to  propagate  with  the  cells.  Finally  he  called  attention  to  the  possible  relation 
of  helminthia  and  cancer  and  felt  that  this  hypothesis  was  in  accord  with  the  frequent 
tumors  of  the  digestive  tracts  and  the  appendix.  He  thought  that  the  endemic  occur- 


498  BULLETIN  OP  THE  BUREAU  OP  FISHERIES. 

rence  of  cancer  in  animals  might  be  explained  by  the  distribution  of  some  nematode  or 
other  carrier. 

Regaud  (1907)  reported  two  rats  in  one  of  which  he  found  at  autopsy  a  general 
sarcomatosis  of  the  peritoneum.  At  the  border  of  the  liver  hung  a  cyst  which  contained 
a  cysticercus.  The  neoplasm  was  a  sarcoma  with  fusiform  elements.  Inoculation  into 
five  rats  remained  negative.  The  second,  an  adult  male,  having  been  found  dying 
without  known  cause,  was  killed.  In  the  peritoneum  a  tumor  the  size  of  a  nut  had  devel- 
oped in  the  large  omentum.  There  were  numerous  miliary  granulations  around  the 
tumor.  At  the  center  of  it  was  a  smooth  cavity  containing  a  tapeworm  25  centimeters 
long  and  living.  Intraperitoneal  inoculations  made  in  five  rats  were  negative.  The 
parasites  in  both  cases  were  identified  as  cysticerci  of  the  Tsenia  crassicola  of  the  cat.  In 
common  with  Borrel,  Regaud  felt  that  the  cysticerci  in  these  instances  were  the  carriers 
of  a  virus,  as  he  had  frequently  found  cysticerci  in  the  liver  of  rats  killed  for  histological 
research  without  accompanying  neoplasms. 

That  a  virus  of  cancer  is  no  longer  hypothetical  has  been  shown  by  the  recent 
demonstration  by  Peyton  Rous  in  three  varieties  of  sarcoma  in  chickens  of  a  filterable 
virus  capable  of  producing  type-true  neoplasms.  This  agent  passes  through  a  medium- 
grade  Berkefeld  filter.  It  is  preserved  by  glycerin,  has  a  killing  point  slightly  higher 
than  the  cells  of  the  chicken,  is  not  injured  by  freezing,  and  is  killed  at  55°  C.  The  agent 
can  be  preserved  by  drying  the  cells  and  can  withstand  grinding.  After  many  months 
the  agent  can  be  separated  from  the  dried  cells  by  filtration,  or,  in  common  with  them, 
on  injection  inaugurates  at  the  point  of  trauma  the  growth  of  a  malignant  sarcoma  of  the 
type  from  which  the  virus  has  been  taken.  Rous  has  separated  the  filterable  virus  from 
a  spindled-celled  sarcoma  (1910),  an  osteo-chrondro-sarcoma  (1912),  and  a  spindle- 
celled  (intracanalicular)  sarcoma  (1913)  with  peculiar  arrangement  of  the  cells.  The 
virus  of  the  osteo-chondro-sarcoma  possesses  the  remarkable  quality  of  causing  the 
connective  tissue  with  which  it  comes  in  contact  to  proliferate  and  specialize  by  forming 
cartilage  and  bone.  His  experiments  not  only  show  the  existence  in  these  tumors  of  a 
filterable  virus  but  the  existence  for  each  type  of  a  special  virus.  It  is  needless  to  point 
out  that  the  agent  of  goiter  is  also  filterable,  which  fact  should  strengthen  the  theory 
that  the  goiter  agent  is  a  living  organism  and  not  a  soluble  toxin. 

Haaland,  Loewenstein,  von  Wasielewski,  and  others  have  found  helminthia  in 
mouse  cancers. 

The  theory  of  Borrel  regarding  nematodes  has  recently  been  experimentally  proven 
by  Fibiger  (1913).  Fibiger  found  in  three  rats  in  his  laboratory  large  papillary  growths 
of  the  stomach,  in  all  of  which  were  many  small  nematode  worms.  These  growths  he 
held  to  be  fibroepithelial  tumors,  probably  malignant,  an  opinion  which  was  strengthened 
by  microscopic  examination.  The  epithelial  proliferation  was  found  to  have  broken 
through  the  muscularis  mucosa,  and  the  submucosa  contained  projections  and  islands 
of  squamous  epithelium.  To  determine  how  frequent  the  disease  might  be  in  Copen- 
hagen, he  examined  1,144  rats  without  finding  any  evidence  of  the  disease.  Later  his 
attention  was  drawn  to  cockroaches  as  possible  carriers  of  such  nematodes,  through  an 
article  by  Caleb  in  1878,  who  found  nematodes  in  the  stomachs  of  rats  after  feeding 


CARCINOMA   OF  THE  THYROID   IN   SALMONOID   FISHES.  499 

them  the  cockroaches,  Periplaneta  orientalis.  These  he  identified  as  Filaria  rhytipleurites 
of  des  Longchamps.  After  examining  61  rats  from  a  locality  in  Copenhagen  which 
was  infested  with  Periplaneta  americana,  he  found  similar  worms  in  the  stomachs  of 
40,  of  which  9  had  well-developed  tumors  and  9  inflammatory  reaction  of  the  mucosa, 
which  he  held  to  be  the  beginning  or  precancerous  stage  of  the  disease.  Furthermore, 
he  reports  that  by  feeding  57  laboratory  rats  with  Periplaneta  americana  from  the  same 
locality  he  found  the  worms  in  the  stomachs  of  54,  in  7  of  which  were  definite  tumors 
and  29  of  which  had  the  precancerous  stage  of  the  disease.  Two  of  these  tumors  were 
found  certainly  to  have  metastases,  probably  three.  The  metastases  did  not  contain 
the  nematodes,  and  furthermore,  Fibiger  states  that  there  is  no  direct  relation  between 
the  intensity  or  amount  of  proliferation  and  the  location  of  the  worms  in  the  gastric 
mucosa. 

The  life  history  of  these  worms  is  as  follows :  They  live  in  the  squamous  epithelium 
of  the  esophagus  and  stomach  of  the  rat.  In  rare  cases  they  are  found  in  the  epithelium 
of  the  tongue  and  the  mouth  cavity.  Here  they  reach  the  reproductive  stage  and  eject 
eggs  which,  with  the  desquamated  epithelium,  are  carried  out  with  the  excreta.  In  the 
excreta  they  are  taken  up  by  the  cockroach  Periplaneta  orientalis,  and  in  these  insects 
the  eggs  develop  into  free  embryos,  wander  into  the  striated  musculature  of  the  pro- 
thorax  and  the  extremities.  Here  they  remain  for  about  six  weeks  or  a  longer  time  as 
trichina-like  spirally  coiled  larvae.  If  the  cockroaches  are  consumed  by  the  rats  the 
larvae  are  freed  from  their  capsules  and  wander  into  the  squamous  epithelium  of  the 
rat's  stomach,  occasionally  into  the  esophagus  or  the  epithelium  of  the  mouth  or  tongue. 
Here  after  two  months  the  female  begins  to  deposit  eggs.  The  measurements  of  these 
worms  in  the  fully  developed  stage  are,  for  the  male,  one-half  to  i  centimeter  long, 
diameter,  o.i  to  0.16  millimeter;  females,  4  to  5  centimeters  long;  diameter,  0.2  to 
0.25  millimeter.  The  eggs  are  oval,  clear,  with  double  contour  membrane,  at  the 
poles  slightly  thicker  than  at  the  circumference.  The  eggs  measure  0.06  by  0.04 
millimeter.  They  contain  a  rolled-up  embryo  with  annular  divisions  of  the  cuticle. 
They  have  been  identified  as  belonging  to  the  genus  Spiroptera.  The  male  has  a  large 
bursa,  with  two  spicules  of  different  lengths  and  four  preanal,  as  well  as  four  postanal 
papillae,  on  each  side,  these  characteristics  serving  to  distinguish  them  from  the  Spiroptera 
obtusa,  as  well  as  from  the  Filaria  rhytipleurites  of  Galeb.  It  is  therefore  a  new 
nematode. 

In  the  sections  of  the  hyperplastic  thyroids  in  our  second  series  of  experimental 
dogs,  we  were  interested  to  find  in  the  capsule  and  in  the  substance  of  the  thyroid  small 
tubercles  measuring  usually  0.3  by  0.35  millimeter,  of  strikingly  uniform  appearance. 
At  the  periphery  of  these  tubercles  is  a  fibrous  connective  tissue  capsule  of  thin  and 
flattened  cells.  Within  the  outer  layer  of  flattened  fibrous  connective  tissue  a  more 
cellular  structure  composes  the  body  of  the  tubercle.  These  are  large  fibroblasts  of 
spindle  form  with  oval,  vesicular  nuclei.  They  have  a  general  arrangement,  as  if  per- 
pendicular to  the  circumference.  The  center  of  the  tubercle  is  composed  of  intercellular 
substance  with  usually  a  zone  of  leucocytes,  and  by  aid  of  serial  sections,  usually  in  the 
center  of  these  tubercles,  one  encounters  a  cross  or  oblique  section  of  a  small  nematode 


500  BULLETIN   OF  THE   BUREAU   OF   FISHERIES. 

worm.  (Fig.  124.)  Occasional  tubercles  will  be  encountered  in  which  either  the  head 
(fig.  123)  or  tail  of  this  worm  lies  near  the  periphery,  and  in  some  instances  a  fully 
formed  tubercle  has  been  encountered  with  cross  sections  of  the  worm  lying  without 
the  connective-tissue  capsule  usually  coiled  in  undulating  fashion.  (Fig.  122.)  The 
worms  appear  to  be  of  the  same1  species.  For  the  purpose  of  identification,  sections  of 
the  worms  have  been  submitted  to  B.  H.  Ransom,  Chief  of  the  Zoological  Division  of 
the  Bureau  of  Animal  Industry  of  the  United  States  Department  of  Agriculture  at 
Washington.  We  are  indebted  to  Dr.  Ransom  for  the  following  notes : 

After  examining  the  preparations  I  fail  to  identify  the  parasite  to  which  you  call  attention  with 
any  known  species.  As  it  is  quite  different  from  a  hookworm  larva  it  is  not  Ancylostoma  caninum  or 
any  other  species  of  hookworm,  a  possibility  which  would  perhaps  first  suggest  itself,  inasmuch  as  the 
larval  stages  of  A  ncylostoma  en  route  to  the  alimentary  tract  are  likely  to  be  found  in  various  tissues, 
though  apparently  they  have  not  yet  been  noted  in  the  thyroid  gland.  As  to  other  possibilities,  so 
far  as  I  have  been  able  to  determine,  no  nematode  has  been  recorded  from  the  thyroid  gland  of  dogs. 
Furthermore ,  the  form  in  question  does  not  agree  in  morphology  with  any  adequately  described  nema- 
tode known  to  occur  in  the  dog  in  any  part  of  the  body. 

The  nematodes  in  this  case,  which  are  sexually  undeveloped,  may  be  (i)  immature  stages  of  some 
species  which  occur  in  its  adult  stage  in  the  dog  and  whose  larvae  after  gaining  entrance  to  the  body 
perform  more  or  less  extensive  migrations  before  reaching  their  final  location,  and  would  thus  be  com- 
parable to  Ancylostoma,  whose  larvae  regularly  migrate  from  the  skin  to  the  digestive  tract,  or  to  Spirop- 
tera  sanguinoknta,  whose  larvae,  it  is  stated,  sometimes  migrate  from  the  digestive  tract  to  the  blood 
vessels  and  other  rather  remote  locations  where  development  to  maturity  may  occur;  (2)  they  may 
conceivably  belong  to  some  species  like  Ollulanus  tricuspis,  whose  young,  according  to  Leuckart,  may 
either  pass  out  of  the  body  to  become  encysted  in  an  intermediate  host  or  penetrate  into  various  tissues 
of  the  original  host  and  become  encysted  in  the  manner  of  Trichinella;  (3)  they  may  be  the  larval  stage 
of  some  species  whose  adult  stage  occurs  in  another  host,  the  dog  acting  as  a  true  though  perhaps  unusual 
intermediate  host;  or  (4)  they  may  be  present  in  the  dog  as  the  result  of  an  accidental  infection  entirely 
outside  the  normal  life  cycle,  this  case  being  comparable  to  that  of  the  infestation  of  mice  and  other 
animals  with  the  larvae  of  Spiroptera  sanguinolenta  to  which  Seurat  (1912,  Compt.  rend.  Soc.  de  biol., 
Paris,  v.  73,  p.  279)  has  called  attention.  This  author  notes  that  these  larvae  which  are  found  in  cock- 
roaches, instead  of  developing  to  maturity  as  when  fed  to  dogs,  if  fed  to  white  mice  pass  through  the 
wall  of  the  digestive  tract  and  become  encapsuled  in  various  organs  without  undergoing  further  devel- 
opment. The  possibility  last  suggested  (4)  is  also  comparable  to  that  of  the  migrations  of  the  larvae 
of  Ancylostoma  duodenale,  a  human  parasite,  in  dogs.  The  larvae  of  this  species  penetrate  the  skin  of 
dogs  and  in  course  of  time  may  reach  the  intestine,  undergoing  a  partial  development  which,  however, 
falls  short  of  maturity. 

As  a  rule  when  nematodes  or  other  parasites  are  found  in  a  given  host  it  is  to  be  presumed  that 
the  animal  is  playing  the  part  of  a  true  host  and  that  there  is  a  more  or  less  complete  adaptation  between 
the  host  on  one  hand  and  the  parasite  on  the  other.  The  possibility,  however,  should  noif  be  lost  sight 
of  that  larval  nematodes  of  an  unknown  species  found  in  a  certain  host,  or  of  a  known  species  found 
in  an  unusual  host,  may  represent  individuals  which  have  gone  astray  so  far  as  the  possibility  of  com- 
pleting their  normal  life  cycle  is  concerned.  It  is  apparently  true  that  nematodes  which  thus  go  astray 
usually  die  before  there  is  any  development  or  any  invasion  of  the  tissues  of  the  animal.  That  is, 
nematodes  entering  the  digestive  tract  of  an  animal  which  is  unsuitable  as  a  host  as  a  rule  quickly 
succumb  without  doing  any  damage.  This  is,  however,  not  the  case  with  all  species,  for  example, 
Spiroptera  sanguinolenta  in  mice,  as  noted  above.  Similarly  in  the  case  of  nematodes  whose  normal 
mode  of  entrance  is  through  the  skin  it  is  to  be  presumed  that  they  will  not  even  enter  the  skin  of  an 
unsuitable  host,  but  such  occurrences  may  not  be  very  unusual.  The  case  of  Ancylostoma  duodenale 
already  mentioned,  and  that  of  Strongyloides  stercoralis,  another  human  parasite,  which  behaves  much 


CARCINOMA  OF  THE  THYROID   IN   SALMONOID   FISHES.  501 

as  A .  duodenale  with  reference  to  dogs,  are  sufficient  to  indicate  that  stray  parasites  may  enter  the  body 
through  the  skin  as  well  as  through  the  mouth,  and  perform  extensive  migrations  through  the  tissues 
and  even  undergo  a  partial  development  before  they  die.  The  possibilities  as  to  the  amount  of  damage 
such  stray  parasites  may  do  are  interesting.  They  may,  for  instance,  have  more  injurious  effects  on 
the  unusual  host  than  on  the  animal  to  which  they  are  specifically  adapted,  much  as  in  the  case  of 
various  parasitic  protozoa  which  do  not  injure  certain  animals  considered  to  be  their  usual  hosts,  but 
are  very  injurious  to  others  considered  unusual  hosts.  The  two  cases  are  of  course  not  strictly  com- 
parable as  there  would  be  no  multiplication,  at  least  no  repeated  multiplication,  in  the  case  of  the 
nematode  like  that  in  the  case  of  the  protozoan.  The  introduction  of  microorganisms  by  nematode 
larvae  is  another  possible  source  of  damage,  and  this  applies  not  only  in  the  case  of  stray  parasites  but 
in  the  case  of  those  entering  their  proper  host  animals.  Many  parasitic  nematodes  have  plenty  of 
opportunity  during  the  early  stages  of  their  free  living  existence  while  they  are  actively  feeding  upon 
the  organic  materials  in  the  medium,  commonly  fecal  matter  which  surrounds  them,  to  pick  up  injurious 
microorganisms,  and  these  it  is  quite  conceivable  may  be  carried  with  them  on  their  later  migrations 
and  finally  deposited  where  damage  will  result.  Looss  (1911,  Rec.  Egypt.  Govt.  School  Med.,  Cairo, 
v.  4,  p.  557),  for  example,  suggests  that  Ancylostoma  larvae  which  have  developed  in  feces  might  retain 
some  bacteria  in  their  intestine  and  evacuate  these  as  soon  as  they  arrive  in  the  body  of  their  host,  and 
that  this  if  it  occurred  might  have  something  to  do  with  the  skin  lesions  which  accompany  Ancylostoma 
infections. 

Returning  to  the  nematodes  in  the  thyroid  of  the  dog,  it  has  not  seemed  advisable  to  venture  an 
opinion  as  to  the  genus  or  even  the  family  to  which  the  parasites  may  belong.  In  order  that  they  may 
not  be  left  nameless  I  have  designated  them  as  Agamonematodum  gaylordi,  thus  placing  them  in  a  col- 
lective group,  which  is  used  for  convenience  of  reference  to  include  various  immature  nematodes, 
whose  sexually  mature  stage  is  undetermined.  The  following  brief  description  is  based  on  an  individual 
the  anterior  portion  of  which  is  present  in  the  sections  on  a  slide  labeled  "  Dog  17.  K.  1-22-12.20,  Nem. 
2".  (Fig.  123.) 

AGAMONEMATODUM   GAYLORDI. 

Length  uncertain,  but  apparently  less  than  i  millimeter;  maximum  width  35;*..  Head  apparently 
with  3  lips,  each  supplied  with  a  small  papilla.  Diameter  of  head  at  level  of  papillae  sofi,  increasing  to 
24^  at  a  distance  of  2o/«  from  the  anterior  end,  then  rather  suddenly  constricted  to  20/1,  after  which  the 
diameter  of  the  body  gradually  increases,  reaching  32;*  at  the  level  of  the  nerve  ring,  which  is  located 
about  ioo/i  from  the  anterior  end  of  the  body.  Mouth  very  small,  communicating  directly,  without 
intervening  larynx  or  mouth  capsule,  with  the  esophagus.  Esophagus  near  its  anterior  end 
measures  about  i6//  in  diameter,  is  then  constricted  slightly,  corresponding  with  the  constriction  of 
the  body,  and  gradually  increases  again  in  diameter,  attaining  a  size  of  about  i8/t  in  the  neighborhood  of 
the  nerve  ring.  Length  of  esophagus  uncertain,  but  exceeds  i6o/z.  The  anterior  end  of  the  body  is 
supplied  with  narrow  lateral  cuticular  wings,  which  extend  posteriorly  an  unknown  distance  beyond 
the  esophageal  region. 

Host. — Dog  (Canis  familiar  is}. 

Location. — Thyroid  gland  in  small  tubercles. 

Locality. — Craig  Brook,  Me. 

The  nematodes  were  not  found  in  the  two  dogs  examined  in  1910,  one  of  which  had 
marked  thyroid  hyperplasia  and  the  other  a  nearly  normal  gland,  but  serial  sections  were 
not  available.  In  all  (3)  of  the  puppies  which  had  marked  hyperplasia  and  were  given 
drinking  water  in  which  were  suspended  scrapings  (dog  16,  dog  17,  and  dog  22)  nema- 
todes are  present.  In  the  white  mongrel  adult  dog  with  the  highest  degree  of  diffuse 
parenchymatous  hyperplasia  and  degeneration  (dog  18)  they  are  also  present.  In  the 
control  for  this  dog,  the  mother  of  the  puppies,  which  received  boiled  water  (dog  19), 
they  are  not  present.  In  the  control  puppy  no.  21,  which  received  boiled  water,  they 


502  BULLETIN   OF  THE   BUREAU  OF  FISHERIES. 

are  not  present.  In  the  second  control  puppy,  no.  20,  they  are  present.  It  is  this 
control,  no.  20,  which  is  described  as  having  slight  evidence  of  hyperplasia,  but  as  this 
dog  received  before  the  beginning  of  the  final  experiment,  as  did  also  the  other  controls, 
water  from  pond  10,  it  is  possible  that  it  acquired  the  worms  at  that  time.  The  mother 
dog,  no.  19,  and  the  other  control  puppy,  no.  22,  also  received  pond  10  water  and 
showed  no  evidence  of  hyperplasia  or  nematodes. 

There  is  apparently  no  direct  connection  between  the  hyperplasia  of  the  thyroid 
and  the  nematodes.  As  previously  described,  the  hyperplasia  of  the  thyroid  in  these 
experimental  animals  is  diffuse.  If  the  nematodes  have  any  direct  relation  to  the  experi- 
mental hyperplasia  of  the  thyroid  thus  produced,  it  is  only  as  a  carrier  of  the  virus  of  the 
disease  in  the  manner  which  Borrel  has  suggested  for  tumors  in  mammals.  That  hyper- 
plasia can  result  without  nematodes  or  other  possible  carriers  is  shown  by  the  fact  that 
we  have  not  found  anything  of  the  sort  in  the  hyperplasia  of  the  thyroid  in  the  rats, 
induced  with  water  and  scrapings  from  Craig  Brook.  Bircher  or  the  other  authors 
who  have  produced  experimental  goiter  in  animals  have  not  noted  the  presence  of  nema- 
todes. Nematodes  in  the  region  of  the  thyroid  in  fish  are  certainly  not  necessary  to 
the  development  of  the  disease  in  fish.  We  have  in  one  or  two  instances  found  similar 
tubercles  usually  lying  in  the  subcutaneous  tissue  below  the  floor  of  the  mouth  in  which 
coiled-up  nematode  remains  have  been  found.  A  portion  of  the  cuticle  of  such  a  nema- 
tode  was  sufficiently  preserved  so  that  its  structure  could  be  clearly  made  out.  (Fig.  126.} 
There  is  evidence  in  the  dog  thyroids  that  some  of  the  nematodes  perish.  The  finding 
of  disintegrating  tubercles  is  subject  to  this  interpretation.  (Fig.  125.)  It  is  therefore 
possible  that  in  the  very  early  stages  of  the  transmission  of  the  disease  it  will  be  found 
that  such  nematodes  act  as  occasional  carriers  in  this  affection  and  that  later  they 
disappear.  A  careful  study  of  the  intestinal  contents  of  the  fish  and  the  scrapings 
from  the  fish  troughs  will  be  included  in  the  next  stage  of  this  investigation. 

SUMMARY. 

I.  The  present  investigation  of  thyroid  carcinoma  among  fish  was  begun  by  the 
Director  of  the  Gratwick  Laboratory  in  furtherance  of  the  inquiry  of  that  institution 
into  the  nature  of  cancer  in  man.  Having  brought  it  to  the  attention  of  the  United 
States  Bureau  of  Fisheries  through  the  President  of  the  United  States,  an  investigation 
of  wider  scope  resulted,  based  upon  its  interest  and  importance  to  fish  culture  and  to 
cancer  research  in  general,  and  uniting  the  Federal  and  State  resources  as  represented 
by  the  Bureau  and  the  Gratwick  Laboratory. 

Bonnet  in  1883  described  a  gill  disease  in  trout  which  is  undoubtedly  identical  with 
the  subject  of  this  inquiry,  and  is  thus  the  first  published  reference  to  it,  though  the 
nature  of  the  disease  was  not  at  that  time  recognized.  Scott  in  1891  first  identified  the 
disease  as  carcinoma,  without  recognizing  its  relation  to  the  thyroid  gland.  Its  origin 
in  the  thyroid  was  first  asserted  by  Plehn  in  1902,  who  diagnosed  it  as  adeno-carcinoma. 
Pick  in  1905  published  the  first  extended  study  of  the  structure  of  the  growths  and 
insisted  on  their  carcinomatous  nature.  Gillruth  in  1902  described  it  briefly  as  an 


CARCINOMA   OP  THE   THYROID   IN   SAL,MONOID   FISHES.  503 

epithelioma  affecting  the  branchial  arches  and  showed  that  it  was  widely  distributed 
among  the  hatcheries  of  New  Zealand. 

Gaylord  began  the  study  of  the  disease  in  1908  and  reported  evidence  pointing  to 
an  infectious  factor  in  its  causation.  Marine  and  I/enhart,  as  the  result  of  studies  in 
1909  and  subsequently,  hold  that  the  disease  is  endemic  goiter  and  have  failed  to  find 
any  specimens  which  they  recognize  as  cancer. 

The  disease  is  widely  distributed  throughout  the  United  States  and  probably  occurs 
more  or  less  everywhere  that  artificial  propagation  of  salmonoids  is  carried  beyond  the 
early  stages. 

II.  The  normal  thyroid  follicles  in  salmonoids  resemble  those  of  the  mammalian 
thyroid,  but  the  gland  is  not  encapsulated  and  not  so  definitely  confined  within  given 
limits.     In  wild  brook  trout  the  largest  masses  of  thyroid  follicles  are  faintly  macro- 
scopic, and  all  the  thyroid  tissue  is  located  in  the  neighborhood  of  and  chiefly  dorsal  to 
the  ventral  aorta  between  the  first  and  third  gill  arches,  and  does  not  extend  laterally 
along  the  arches.     The  distribution  is  somewhat  more  restricted  than  that  indicated  by 
Gudernatsch.     Anomalous  deposits  frequently  occur  beneath   the  epithelium  of  the 
jugular  pit,  but  are  rare  elsewhere.     The  thyroid  follicles  of  wild  trout  are  regular  in 
shape,  usually  spherical  or  slightly  elongate  and  in  the  typical  or  simplest  condition  its 
epithelium  is  flattened  or  never  higher  than  cuboidal. 

III.  Simple  hyperplasia  of  the  thyroid  is  met  with  in  trout  living  under  wild  condi- 
tions.    The  follicles  are  increased  in  number,  are  more  irregular  in  shape,  the  colloid  is 
diminished,  and  the  epithelium  is  in  large  part  columnar.     Such  a  hyperplasia  exists 
also  in  domesticated  trout  and  is  not  to  be  distinguished  from  the  earliest  stages  of 
carcinoma  of  the  thyroid.     The  immune  Scotch  sea  trout  as  yearlings  occasionally 
exhibit  this  simple  hyperplasia,  and  a  few  adults  are  found  with  colloid  goiter.     Sponta- 
neous recovery  from  thyroid  carcinoma  in  fish  does  not  result  in  this  picture  of  colloid 
goiter. 

IV.  The  first  macroscopic  evidence  of  the  disease  is  usually  found  in  an  area  of 
hyperemia  on  the  floor  of  the  mouth  (red  floor).     The  first  evidence  of  visible  tumors 
may  be  found  at  the  branchial  junction.     Tumors  may  protrude  in  various  directions, 
at  the  branchial  junction,  in  the  floor  of  the  mouth,  or  to  either  side  of  the  gill  region. 
Independent  tumors  develop  in  the  jugular  pit,  a  region  which  frequently  contains 
deposits  of  normal  thyroid  tissue.     The  first  microscopic  evidence  of  the  disease  is 
found  to  occur  in  individual  follicles,  usually  those  nearest  a  large  vessel.     A  small 
group  of  altered  follicles  surrounded  by  normal  follicles  is  frequently  found  in  the  early 
stages.     The  epithelium  is  high  cubical  or  columnar,  the  protoplasm  and  nuclei  stain 
deeply.     Colloid  is  diminished  or  absent,  the  vessels  of  the  stroma  hyperemic.     Budding 
of  the  wall  of  the  follicle  next  occurs,  forming  isolated  npw  follicles  of  irregular  type, 
and  papillary  projections  into  the  follicles.     As  the  gland  is  not  encapsulated,  newly 
formed  tissue  grows  between  the  muscle  planes  and  fills  in  the  areolar  spaces.     At  this 
stage  karyokinetic  figures  are  common,  the  epithelium  is  high  columnar,  and  frequently 
there  are  several  layers  of  epithelium  in  a  single  follicle.     Proliferation  may  now  have 


504  BULLETIN   OF  THE   BUREAU  OP  FISHERIES. 

reached  a  sufficient  amount  to  produce  the  red-floor  stage.  Bone,  cartilage,  and  muscle 
are  invaded.  The  growth  no  longer  seeks  the  paths  of  least  resistance. 

In  the  visible  tumor  stage  there  is  a  remarkable  variation  in  the  character  of  the 
proliferation.  All  the  various  types  occur  in  one  tumor.  They  may  be  divided  into 
alveolar,  tubular,  and  solid,  and  combined  with  papillary  and  cystic  types.  Frequently 
small  adenomatous  structures  of  malignant  appearance  are  found  grading  and  infil- 
trating the  surrounding  thyroid  structure  of  less  malignant  appearance.  Occasionally 
islands  of  normal  thyroid  tissue  have  been  found  in  the  bone  spaces  or  cavities  of  the 
bone  where  the  entire  surrounding  structure  was  replaced  by  thyroid  carcinoma.  True 
infiltration  of  bone,  cartilage,  vessel  wall,  muscle,  and  skin  has  been  demonstrated. 
Occasionally  tumors  are  met  with  which  present  the  appearance  of  so-called  sarco- 
carcinoma  of  the  thyroid  in  mammals;  a  background  of  spindle  cells  resembling  sarcoma 
with  occasional  alveoli. 

Growths  upon  the  apex  of  the  lower  jaw  are  either  implantations  or  metastases. 
A  marked  similarity  of  the  primary  tumor  in  the  thyroid  region  with  the  growth  upon 
the  tip  of  the  jaw  in  one  case  studied  indicates  that  this  is  probably  metastasis  formation 
at  the  site  of  an  injury.  An  undoubted  case  of  metastasis  formation  is  found  in  a  tumor 
growing  in  the  intestinal  wall  at  the  lower  end  of  the  intestinal  tract,  which  infiltrated 
the  muscularis  mucosa  of  the  intestinal  wall,  of  characteristic  thyroid  carcinoma  struc- 
ture, large  irregular  follicles  lined  with  columnar  epithelium,  occasionally  containing 
colloid.  Portions  of  the  tumor  present  an  appearance  closely  approximating  the  least 
malignant  appearing  primary  tumors.  The  character  of  this  growth  and  the  region  in 
which  it  occurred  shows  conclusively  that  it  is  a  metastasis. 

A  comparison  of  the  various  types  of  thyroid  carcinoma  of  the  Salmonidge  shows 
that  they  approximate  in  type  three  of  the  groups  made  by  Langhans  for  carcinoma  of 
the  thyroid  in  mammals,  viz,  proliferating  struma,  carcinomatous  struma,  and  malignant 
papilloma. 

V.  Three  examples  of  the  disease  have  been  found  in  wild  fish  in  the  United  States. 
One  occurred  in  a  brook  trout  which  may  have  been  planted  from  a  hatchery,  one  in 
a  landlocked  salmon,  and  one  in  a  whitefish.     None  of  the  species  of  whitefishes  is  fed 
or  reared  artificially. 

VI.  The  disease  has  been  observed  in  16  species  of  salmonoids,  or  in  hybrids  made 
among  these. 

The  geological  formation  at  the  sources  of  the  water  supplies  in  which  the  disease 
occurs  has  apparently  nothing  to  do  with  its  origin,  nor  has  the  dissolved  content  of 
the  water. 

The  disease  is  usually  endemic  and  occasionally  epidemic.  It  occurs  in  ponds  and 
troughs,  of  whatever  construction,  in  which  fish  are  held,  reared,  and  fed  the  ordinary 
proteid  foods  of  fish  culture,  viz,  raw  liver,  heart,  lungs,  and  other  meats.  It  shows  a 
tendency  to  increase  from  above  downward  in  the  course  of  a  given  water  flow.  Hybrids 
of  the  Pacific  salmon  are  especially  susceptible  and  show  a  high  incidence.  When 
endemic,  the  course  of  the  disease  is  slow  and  chronic,  with  a  low  death  rate  made 
indeterminate  by  complication  with  intercurrent  or  terminal  infection  and  other 
causes  of  death.  The  incidence  of  tumors  varies  greatly  and  increases  with  the  age  of 


CARCINOMA   OF  THE)   THYROID   IN   SAIyMONOID   FISHES.  505 

the  fish.  Macroscopically  visible  growths  have  not  been  seen  in  fish  under  about  five 
months  of  age.  Anemia  and  cachexia,  sometimes  extreme  in  degree,  are  a  frequent 
but  not  constant  accompaniment  of  the  disease.  Immunity  is  strikingly  exhibited  not 
only  among  species,  as  the  Scotch  sea  trout,  but  with  given  lots  of  a  susceptible  species. 
Recovery  or  regression  occurs  when  affected  fish  are  removed  from  domestication  to 
wild  conditions  and  also  in  fish  in  ponds  in  which  the  disease  was  acquired. 

VII.  Feeding  of  fish  tumors,  or  of  human  cancer,  to  brook  trout  has  not  during  a 
period  of  several  months  produced  the  slightest  evidence  of  the  disease  attributable  to 
this  feeding.     The  intimate  association  of  susceptible  trout  with  trout  tumor  material 
in  standing  water,  or  with  tumor  fish  in  circulating  unchanged  water,  has  brought  only 
negative   results.     The  fish   tumor   has   not   yet   been   successfully  transplanted,  but 
implants  have  grown  slightly  and  were  alive  at  the  end  of  three  months.     The  tumor 
extract  is  highly  toxic  to  trout  when  injected  into  the  thyroid  region  or  subcutaneously. 

Wild  brook  trout  brought  from  the  wilderness  and  confined  in  cement  tanks  and 
fed  raw  heart  or  raw  liver  have  developed  microscopic  evidence  of  the  disease  by  the 
end  of  the  first  year,  and  visible  carcinoma  between  the  first  and  second  year.  The 
feeding  of  cooked  liver  retarded  the  process.  Spontaneous  regression  occurred  in  a 
high  percentage  of  the  meat-fed  fish  by  the  end  of  the  second  year.  Similar  trout  fed 
upon  marine  fish,  vegetable  food,  or  a  combination  of  mussels  and  live  maggots  retained 
their  normal  thyroids. 

VIII.  Either  of  the  elements  iodine,  mercury,  or  arsenic  dissolved  as  salts  in  the 
water  in  which  the  fish  are  living  interrupts  the  progress  of  the  disease  and  restores  the 
thyroid  epithelium  to  a  condition  approximating  the  normal.     Recognizable  effects  are 
produced  within  a  few  days.     Visible  tumors  are  markedly  affected  and  may  be  much 
reduced  in  size.     Iodine  and  mercury  are  effective  even  when  diluted  by  many  millions 
of  parts  of  water.     Iodine  is  effective  when  introduced  into  the  digestive  tract  as  well 
as  through  the  medium  of  the  water.     Negative  results  were  obtained  with  thymol  by 
both  these  methods  of  administration. 

IX.  The  administration  to  dogs  of  mud  and  water  from  fish  ponds  in  which  thyroid 
carcinoma  was  endemic  gave  suggestive  evidence  that  the  water  and  mud  contained  an 
agent  capable  of  producing  marked  changes  in  the  thyroid.     Scrapings  from  the  inside 
of  old  wooden  fish  troughs  in  which  thyroid  carcinoma  was  constantly  produced  gave 
positive  results.     Four  dogs  were  given  for  six  months  water  to  drink  in  which  these 
scrapings  were  immersed.     All  developed  marked  thyroid  hyperplasia  and  three  of  them 
enlarged  thyroids.     The  thyroids  of  the  three  control  animals  remained  of  normal  size. 
Two  of  them  were  normal  in  structure  while  one  showed  slight  evidence  of  hyperplasia, 
probably  referable  to  a  previous  experiment. 

Rats  given  for  six  months  mud  and  water  which  had  been  taken  from  ponds  in  which 
thyroid  carcinoma  was  prevalent  and  transported  several  hundred  miles  gave  negative 
results.  Rats  given  for  four  months  water  from  the  fish  trough  scrapings,  also  trans- 
ported as  above,  produced  results  similar  to  those  obtained  with  the  dogs  but  less  marked 
in  degree. 

8207° — X4 IO 


506  BULLETIN   OF  THE   BUREAU   OF  FISHERIES. 

X.  In  the  hyperplastic  thyroids  of  three  puppies  and  one  adult  dog  which  were 
given  pond  mud  and  water,  or  water  from  fish-trough  scrapings,  minute  nematode  worms 
were  found  immediately  beneath  the  capsule  or  in  the  .substance  of  the  thyroid.  The 
worms  were  surrounded  by  connective  tissue  tubercles.  In  two  instances  only  remains 
of  small  nematode  worms  were  found  in  the  thyroid  region  of  brook  trout  with  carcinoma 
of  the  thyroid  undergoing  regression.  If  these  worms  have  any  etiological  significance 
it  must  be  merely  as  carriers  of  a  causative  agent. 

CONCLUSIONS. 

1 .  The  disease  known  as  gill  disease,  thyroid  tumor,  endemic  goiter,  or  carcinoma  of 
the  thyroid  in  the  Salmonidae,  is  a  malignant  neoplasm. 

2.  The  disease  occurs  in  fish  living  under  conditions  of  freedom  in  populated  areas. 

3.  When  introduced  into  fish-breeding  establishments  it  becomes   endemic   with 
occasional  epidemic  outbreaks. 

4.  Normal  fish  taken  from  the  wilderness  may  be  made  to  acquire  the  disease  when 
placed  in  fish-breeding  establishments  where  the  disease  is  endemic. 

5.  The  feeding  of  uncooked  animal  proteid  favors  and  the  feeding  of  cooked  animal 
proteid  retards  the  disease  as  compared  with  the  uncooked.     Feeding  alone  is  not  an 
efficient  cause.     It  must  be  combined  with  an  agent  transmitted  probably  through  the 
water  or  food,  or  both. 

6.  By  scraping  the  inner  surface  of  water-soaked  wooden  troughs  in  which  the  disease 
is  endemic,  an  agent  may  be  secured  which  from  its  action  upon  the  mammalian  thyroid 
when  administered  through  drinking  water  is  no  doubt  the  cause  of  the  disease  in  the 
fish  confined  in  these  troughs. 

7.  The  agent  is  destroyed  by  boiling. 

8.  Fish  in  all  stages  of  the  disease  are  favorably  affected  in  the  direction  of  cure  by 
the  addition  to  the  water  supply  in  suitable  concentration  of  mercury,  arsenic,  or  iodine. 

9.  The  effect  of  mercury,  arsenic,  and  iodine  in  carcinoma  of  the  thyroid  in  fish 
and  the  subsequent  positive  experiments  with  metals  in  mammalian  cancer  are  probably 
the  expression  of  a  therapeutic  relation  of  these  elements  to  carcinoma. 

10.  Certain  species  of  the  Salmonidae  have  an  almost  complete  natural  resistance  to 
the  disease. 

11.  Certain  lots  of  fish  of  susceptible  species  show  a  high  degree  of  immunity  to 
the  disease. 

12.  Spontaneous  recovery  occurs  in  a  considerable  percentage  of  individuals. 

13.  Removal  from  ponds  in  which  the  disease  is  endemic  to  natural  conditions, 
or  a  change  to  more  natural  food,  increases  the  percentage  of  spontaneous  recoveries. 

14.  Spontaneous  recovery  appears  to  confer  a  degree  of  immunity  against  recurrence. 

15.  The  percentage  of  spontaneous  recoveries  in  the  early  stages  of  the  disease 
appears  to  be  higher  than  in  the  later  stages  of  the  disease. 

1 6.  The  incidence  of  the  disease  increases  with  the  age  of  the  fish,  at  least  up  to 
five  years. 


CARCINOMA   OF  THE   THYROID   IN   SALMONOID   FISHES.  507 

17.  Thyroid  enlargement  and  changes  presenting  at  the  end  of  five  months  a  picture 
of  diffuse  parenchymatous  goiter  were  induced  in  mammals  by  giving  them  water  to 
drink  in  which  had  been  suspended  scrapings  from  troughs  in  which  the  disease  is 
endemic.     Control  animals  which  receive  the  same  water  boiled  failed  to  develop  thyroid 
changes.     That  these  enlargements  and  changes  are  the  first  stages  in  mammals  of  the 
same  disease  which  occurs  in  the  fish  inhabiting  the  troughs  from  which  the  scrapings 
were  obtained,  is  an  inference  which  we  believe  further  experiments  will  justify. 

1 8.  The  disease  is  endemic  in  a  very  high  percentage  of  all  trout  hatcheries  in  the 
United  States. 

19.  The  occurrence  of  the  disease  in  wild  fish,  its  introduction  into  fish-cultural 
stations,  its  localization  in  certain  troughs  or  water  supplies,  the  method  of  its  spread, 
its  transmission  to  mammals,  the  efficacy  of  three  well-known  inorganic  germicides  in 
the  treatment  of  the  disease,  the  destruction  of  the  agent  by  boiling,  the  phenomena  of 
spontaneous  recovery  and  immunity,  strongly  indicate  that  the  agent  causing  the 
disease  is  a  living  organism. 

20.  No  evidence  has  yet  been  produced  to  indicate  the  direct  transmission  of  the 
disease  from  individual  to  individual. 

21.  In  many  of  its  phases  the  disease  is  identical  with  endemic  goiter.     As  there 
is  no  line  of  demarcation  between  what  is  called  endemic  goiter  and  what  we  believe  we 
have  clearly  shown  is  cancer  of  the  thyroid,  we  hold  that  endemic  goiter  and  carcinoma 
of  the  thyroid  in  the  Salmonidae  are  the  same  disease. 

ZUSAMMENFASSUNG. 

I.  Die  gegenwartige  Untersuchung  des  Schilddriisen-Krebses  unter  den  Fischen 
wurde  von  dem  Leiter  des  Gratwick-Laboratoriums  eingeleitet  zwecks  Foerderung  der 
Untersuchungen  dieses  Institutes  betreffs  der  Natur  des  Krebses  beim  Menschen. 
Nachdem  durch  die  Vermittlung  des  Praesidenten  der  Vereinigten  Staaten  das  Interesse 
unserer  Central-Bureaus  fuer  Fisch-Zucht  gewonnen  war,  nahm  die  Untersuchung  eine 
betrachtliche  Ausdehnung  gestiitzt  auf  die  Wichtigkeit  derselben  fuer  die  Fisch-Zucht 
und  fur  die  Krebs-Forschung  im  Allgemeinen.  So  wurden  fuer  den  Zweck  die  Huelfs- 
kraefte  des  Landes  (Centralbureau  fuer  Fisch-Zucht)  und  des  Einzel-Staates  (Grat- 
wick  Laboratorium)  vereinigt. 

Bonnet  beschrieb  im  Jahre  1883  eine  Kiemen-Erkrankung  der  Forelle,  welche 
zweifellos  mit  dem  Gegenstand  unserer  Untersuchungen  identisch  ist,  und  dies  ist  die 
erste  diesbezuegliche  Mitteilung,  wenn  auch  die  Natur  der  Erkrankung  damals  nicht 
erkannt  worden  war.  Scott  erklaerte  die  Erkrankung  im  Jahre  1891  als  erster  fuer 
Krebs,  ohne  ihre  Beziehung  zur  Schilddruese  zu  erkennen.  Ihr  Entstehen  in  der 
Schilddruese  wurde  zuerst  von  Plehn  im  Jahre  1902  behauptet,  welcher  die  Krank- 
heit  als  ein  Adeno-Carcinom  diagnostizierte.  Pick  veroeffentlichte  als  erster  im  Jahre 
1905  eine  eingehende  Erforschung  der  Struktur  dieser  Neubildungen  und  erklaerte 
sie  absolut  fuer  Krebs-Tumoren.  Gilruth  beschrieb  dieselben  in  1902  als  Epitheliom 
der  Kiemenboegen  und  wies  nach,  das  sie  in  den  Fisch-Brutanstalten  Neu-Seelands 
sehr  verbreitet  waren. 


508  BULLETIN  OP  THE   BUREAU  OF  FISHERIES. 

Gaylord  began  das  Studium  der  Erkrankung  im  Jahre  1908  und  berichtete  Tat- 
sachen,  welche  auf  eine  Infektion  als  Ursache  hinwiesen.  Marine  und  Lenhart  behaupte- 
ten  im  Jahre  1909  und  spaeter  als  das  Resultat  ihrer  Untersuchungen,  dass  die  Krank- 
heit  ein  endemischer  Kropf  waere.  Sie  konnten  in  ihren  Praeparaten  keinen  Krebs 
feststellen. 

Die  Erkrankung  ist  in  den  Vereinigten  Staaten  weit  verbreitet  und  kommt  wahr- 
scheinlich  mehr  oder  weniger  ueberall  vor,  wo  die  Ziichtung  von  Salmoniden  ueber  das 
frueheste  Stadium  hinaus  fortgefuehrt  wird. 

II.  Die  Follikel  der  normalen  Schilddruese  in  der  Lachs-Gruppe  aehneln  denen 
der  Saeugetier-Schilddruese,  aber  die  Druese  ist  nicht  eingekapselt  und  nicht  so  scharf 
abgegrenzt.     Bei  der  wilden  Bach-Forelle  sind  die  groessten  Haufchen  der  Follikel 
makroskopisch   eben  wahrnehmbar,   und   das  gesammte  Schilddruesengewebe  ist  in 
der  Naehe  der  Ventral-Aorte  hauptsaechlich  dorsalwaerts  derselben  gelagert  zwischen 
dem  ersten  und  dritten  Kiemenbogen.     Sie  dehnen  sich  nicht  lateralwaerts  langs  den 
Kiemenboegen  aus.     Die  Lage  is  mehr  beschraenkt  als  nach  der  Angabe  von  Guder- 
natsch.     Haeufig  sieht   man   anomale   Follikel-Anhaeufungen  unter  dem  Epithel  der 
Jugular- Vertiefung,    aber   kaum    irgend    wo   anders.     Die   Schilddruesen-Follikel   der 
wilden  Forelle  sind  von  regelmaessiger  Gestalt,  gewoehnlich  kugelig  oder  langlichrund, 
in  der  typischen  oder  einfachsten  Form  haben  sie  ein  flaches,  jedenfalls  nie  hoeher  als 
wurfelformiges  Epithel. 

III.  Einfache  Hyperplasie  der   Schilddruese  findet  man  bei  der  wilden  Forelle. 
Die  Follikel  sind  zahlreicher,  unregelmassiger  in  Form,  das  Colloid  ist  vermindert  und 
das  Epithel  ist  zum  grossen  Teil  saulenformig.     Solch  eine  Hyperplasie  kommt  auch 
beider  zahmen  Forelle  vor,  und  dieselbe  lasst  sich  nicht  von  dem  friihsten  Stadium 
des   Schilddruesen-Krebses   unterscheiden.     Die   immune   See-Forelle    (Salmo  trutta) 
zeigt  gelegentlich  im  ersten  Jahr  diese  einfache  Hyperplasie  und  im  ausgewachsenen 
Zustand  findet  man  einzelne  mit  colloidem  Kropf.     Spontanheilung  des  Schilddriisen- 
Krebses  beim  Fisch  zeigt  nicht  dieses  Bild  des  colloiden  Kropfes. 

IV.  Das  erste  makroskopische  Anzeichen  der  Erkrankungen  ist  gewohnlich  ein 
hyperamischer  Fleck  in  dem  Boden  der  Mundhohle  (red  floor) .     Das  erste  Zeichen  einer 
sichtbaren  Neubildung  findet  man  an  der  Kiemenbogen-Vereinigung.     Deutliche  Tu- 
moren  konnen  entweder  hier  oder  auf  dem  Boden  der  Mundhohle  oder  zu  beiden  Seiten 
der  Kiemenbogen  hervorwachsen.     Selbstandige  Tumoren  entwickeln  sich  in  der  Jugular- 
Vertiefung,  woselbst  nicht  selten  Anhaufungen  von  normalem  SchilddrusenOewebe  zu 
finden  sind.     Die  ersten  mikroskopischen  Anzeichen  der  Erkrankung  findet  man  in 
vereinzelten  Follikeln,  gewoehnlich  denen  welche  einem  grossen  Blutgefass  benachbart 
sind.     Eine  kleine  Gruppe  von  veranderten  Follikeln  sieht  man  oft  im  Fruhstadium 
umgeben  von  normalem  Gewebe.     Das  Epithel  ist  wiirfel-  oder  saulenformig,  das  Proto- 
plasma  und  die  Kerne  im  gefarbten  Praparat  sind  stark  gefarbt.    Colloid  ist  vermindert 
oder  nicht  vorhanden,  die  Gefasse  des  Stromas  sind  hyperamisch.     Demnachst  stellt 
sich  Wucherung  der  Follikel  wand  ein,es  bilden  sich  neue  Follikel  von  unregelmassiger 
Gestalt  und  papillenartige  Auswiichse  in  die  Follikeln.     Da  die  Druse  keine  Kapsel  hat, 
wachst  das  neugeformte  Gewebe  in  die  Muskelbiindel  hinein  und  f ullt  die  Areolar-Raume. 


CARCINOMA  OF  THE  THYROID  IN  SALMONOID  FISHES.  509 

In  diesem  Stadium  sind  karyokinetische  Bilder  sehr  gewohnlich,  das  Epithel  ist  hoch- 
saulenformig,  haufig  findet  man  mehrere  Epithel-Lagen  in  einem  einzelnen  Follikel.  Die 
Wucherung  kann  jetzt  so  weit  fortgeschritten  sein,  dass  sie  das  "rote  Boden"  Stadium 
erreicht.  Die  Neubildung  verfolgt  nun  nichtmehr  den  Weg  des  geringsten  Widerstandes. 
In  diesem  Stadium  des  deutlich  sichtbaren  Tumors  zeigt  derselbe  eine  auffallende 
Character- Verschiedenheit  im  Wachstum.  Sammtliche  Typen  konnen  in  einem  Tumor 
vorkommen.  Man  kann  alveolare,  tubulare  und  solide  Formen  unterscheiden,  welche 
im  Verein  mit  papillaren  und  cystischen  Typen  auftreten  konnen.  Haufig  findet  man 
kleine  adenomatose  Gewebshaufchen  von  bosartigem  Aussehen,  welche  in  das  umge- 
bende,  weniger  bosartig  aussehende  Schilddriisengewebe  hineinwachsen  und  dasselbe 
durchdringen.  Manchmal  fanden  sich  Inseln  von  normalem  Schilddriisengewebe  in  den 
Knochenraumen  oder  in  den  Knochenhohlen,  wo  das  gesammte  umgebende  Gewebe 
durch  Schilddrusen-Krebs  ersetzt  war.  Es  liess  sich  wirkliche  Infiltration  des  Knochens, 
des  Knorpels,  der  Gefass-Wandung,  des  Muskels  und  der  Haut  nachweisen.  Manchmal 
stosst  man  auf  Tumoren,  welche  das  Bild  des  sogenannten  Sarco-Carcinom  der  Saugetier- 
Schilddriise  geben;  ein  Hintergrund  von  Spindel-Zellen  wie  beim  Sarkom  mit  einer 
Alveole  hier  und  da.  Tumoren  an  der  Spitze  des  Unterkiefers  sind  entweder  Implanta- 
tionen  oder  Metastasen.  Eine  deutliche  Ahnlichkeit  des  primaren  Tumors  in  der  Schild- 
driisen-Gegend  mit  der  Wucherung  an  der  Spitze  des  Kiefers,  welche  wir  in  einem  Falle 
untersuchten,  zeigte  dass  letztere  wahrscheinlich  eine  Metastase  an  einer  verletzten 
Stelle  war.  Einen  unzweifelhaften  Fall  von  Metastasis  fanden  wir  in  einer  Neubildung 
in  der  Darm-Wandung  am  untern  Ende  des  End-Darms.  Dasselbe  wuchs  in  die  Muscu- 
laris  mucosa  des  Darms,  zeigte  den  typischen  Schilddriisen-Krebs-Bau,  grosse  unregel- 
massige  Follikel  gesaumt  mit  saulenartigem  Epithel,  hier  und  da  etwas  Colloid.  Teile 
derGeschwulst  sehen  aus  wie  die  am  wenigsten  bosartig  aussehenden  primaren  Tumoren. 
Der  Character  dieser  Neubildung  und  die  Localitat  beweisen  deutlich  dass  es  eine  Meta- 
stase ist.  Eine  Vergleichung  der  verschiedenen  Formen  des  Schilddriisenkrebses  in  den 
Salmoniden  zeigt,  dass  sie  im  Grossen  und  Ganzen  den  drei  Gruppen  entsprechen,  welche 
Langhans  f uer  den  Schilddriisenkrebs  bei  Saugetieren  auf stellt,  namlich :  Wuchernder 
Kropf ,  krebsartiger  Kropf  und  bosartiges  Papillom. 

V.  Drei  Falle  der  Erkrankung  haben  wir  in  den  Vereinigten  Staaten  beim  Fisch  im 
Wildzustand  gefunden,  einen  bei  einer  Bach-Forelle,  welche  vielleicht  aus  einer  Fisch- 
Ziichterei  verpflanzt  worden  war.     Die  zwei  andere  betraf  einen  "Weissfisch"  (Core- 
gonus)  und  ein  Lachs  (Salmo  sebago).     Bei  dem  Coregonus  findet  weder  kunstliche  Fiit- 
terung  noch  Ziichtung  statt. 

VI.  Die  Erkrankung  wurde  in  16  Arten  der  Familie  "Lachs"  beobachtet  oder  in 
deren  Kreuzungsformen.     Die  geologische  Formation  des  Bodens  in  der  Umgebung 
der  Gewasser  und  ihrer  Quellen,  in  denen  die  Krankheit  an  Fischen  beobachtet  worden 
ist,  hat  wahrscheinlich  nichts  mit  ihrem  Ursprung  zu  thun,  ebenso  wenig  die  im  Wasser 
gelosten  Bestandteile.     Die  Erkrankung  ist  gewohnlich  endemisch,  zuweilen  epidemisch. 
Sie  kommt  vor  in  Teichen  und  Wasserbehaltern,  was  immer  auch  die  Construction 
sein  mag,  in  welchen  Fische  gehalten,  geziichtet  und  mit  der  gebrauchlichen   Pro- 
teinhaltigen   Nahrung  gefiittert  werden:    Roher  Leber,   Herz,   Lunge   und   anderen 
animalen  Bestandteilen.     Beim  Verfolgen  eines  Flussgebiets  stromabwarts  sieht  man 


510  BULLETIN   OF  THE   BUREAU   OF   FISHERIES. 

eine  Zunahme  in  der  Affektion.  Kreuzungen  mit  dem  Lachs  des  Stillen  Oceans  sind 
besonders  emfanglich  und  zeigen  eine  hohe  Krankheits-Ziffer.  Die  endemische  Form 
verlauft  langsam,  chronisch  mit  einer  niedrigen  Sterberate,  welche  selbst  sicherer  fest- 
zustellen  ist  wegen  der  Complication  mit  intercurrenten  Affektionen  und  der  schliesslichen 
Infektion.  Das  Vorkommen  des  Tumors  schwankt  sehr  und  nimmt  mit  dem  Alter  des 
Fisches  zu.  Makroskopisch  sichtbare  Neubildungen  waren  erst  nach  dem  fiinften 
Lebensmonat  des  Fisches  bemerkbar.  Anamie  und  Cachexie,  zuweilen  sehr  hochgradig, 
waren  eine  haufige  aber  nicht  constante  Begleit-Erscheinung.  Immunitat  zeigt  sich  in 
auffallender  Weise  nicht  nur  bei  einzelnen  Arten  wie  bei  der  See-Forelle,  sondern  auch 
bei  Arten  welche  fur  die  Erkrankung  empfanglich  sind.  Heilung  oder  Riickbildung 
kommt  vor,  wenn  die  erkrankten  Individuen  in  Verhaltnisse  absoluten  Naturzustandes 
iibergef  iihrt  werden  und  auch  wenn  Fische  in  Teichen  weiter  gehalten  werden,  in  welchen 
sie  erkrankten. 

VII.  Fiittern  von  Bachforellen  mit  Fisch-Tumoren  oder  mit  Krebs  vom  Menschen 
wahrend  einer  Periode  von  meheren  Monaten  gab  nicht  den  geringsten  Beweis,  dass  eine 
Erkrankung  solchem  Fiittern  zuzuschreiben  sei.     Innige  Beriihrungen  von  empfang- 
ilichen  Forellen  mit  Forellen-Tumor-Material  in  stagnierendem  Wasser  oder  mit  tumor- 
behafteten  Fischen  in  circulierendem  unverandertem  Wasser  brachte  uns  nur  negative 
Resultate.     Der  Fischtumor  hat  sich  noch  nicht  mit  Erfolg  transplantieren  lassen,  aber 
Implantationen  gelangen  bis  zu  einem  gewissen  Grade,  und  dieselben  waren  nach  Verlauf 
von  3  Monaten  lebensfahig.     Der  Tumor-Extract  ist  hochgradig  giftig  fur  die  Forelle, 
wenn  derselbe  in  die  Schilddriise  oder  subcutan  injiciert  wird.     Wilde  Forellen  wurden 
aus  ihrer  natiirlichen  Umgebung  in  Cement-Behalter  gebracht  und  mit  ungekochter 
Leber  and  Herz  gefiittert.     Dieselben  zeiten  die  mikroskopisch  nachweisbare  Erkran- 
kung am  Ende  des  ersten  Jahres  und  sichtbaren  Krebs  zwischen  dem  ersten  und  zweiten 
Jahr.     Fiitterung  mit  gekochter  Leber  verzogerte  den  Prozess.     Spontane  Riickbildung 
war  in  einem  grossen  Prozentsatz  der  fleischgefiitterten  Fische  am  Ende  des  zweiten 
Jahres  nachweisbar.     Forellen  derselben  Art  mit  Salzwasser-Fisch,  Vegetabilien  oder 
einer  Mischung  von  Muscheln  und  lebenden  Wiirmern  genahrt  behielten  ihre  normale 
Schilddriise. 

VIII.  Jod,  Quecksilber  und  Arsen  in  ihren  Salzverbindungen  im  Wasser  gelost,  in 
welchem  die  Fische  leben,  unterbrechen  das  Fortschreiten  der  Erkrankung  und  stellen 
beinahe  den  Normal-Zustand  des  Schilddriisen-Epithels  wieder  her.     Ein   deutlicher 
Einfluss    ist    schon    nach    wenigen    Tagen    bemerkbar.     Sichtbare    Tumoren    werden 
wahrnehmlich  beeinflusst  und  konnen  betrachtlich  schrumpfen.     Jod  und  Quecksilber 
sind  schon  im  millionenfacher  Verdiinnung  wirksam.     Jod  ist  wirksam,  wenn  in  den 
Verdauungstractus  gebracht  und  durch  die  Vermittlung  des  Wassers.     Nach  beiden 
Richtungen  hin  waren  Versuche  mit  Thymol  ohne  Einfluss. 

IX.  Schlamm  und  Wasser  von  Fischteichen,  in  welchen  Schilddriisenkrebs  ende- 
misch  war,  wurde  an  Hunde  verfiittert.     Es  zeigte  sich,  dass  das  Wasser  ein  Agens 
enthielt,  welches  imstande  war,  deutliche  Veranderungen  in  der  Schilddriise  zu  verur- 
sachen.     Material,  welches  von  der  Innenseite  alter  Fischbehalter  abgekratzt  worden 
war,  in  denen  bestandig  Schilddriisenkrebs  produciert  worden  war,  gab  positive  Resultate 


CARCINOMA   OF  THE   THYROID   IN   SALMONOID   FISHES.  511 

Vier  Hunde  wurden  6  Monate  lang  mit  Wasser  getrankt,  dem  dieses  Material  beigesetzt 
war.  Sie  zeigten  sammtlich  ausgesprochene  Hyperplasie  der  Schilddriise,  und  drei 
batten  vergrosserte  Schilddrusen.  Die  Schilddrusen  der  3  Control-Tiere  blieben  normal 
in  Grosse.  Zwei  davon  waren  normal  in  Bau,  wahrend  eine  leichte  Hyperplasie  zeigte, 
wahrscheinlich  aus  Griinden  eines  friiheren  Experiments.  Ratten  wurden  6  Monate 
lang  mit  Schlamm  und  Wasser  aus  Teichen  gefiittert,  in  denen  Schilddriisenkrebs  vor- 
herrschend  war.  Dies  Wasser  musste  mehrere  hundert  Meilen  transportiert  werden. 
Das  Resultat  war  negativ.  Das  obenerwahnte  abgekratzte  Fischbehalter  material 
wurde  4  Monate  lang  in  Wasser  an  Ratten  verf iittert.  Das  Wasser  wurde  ebenfalls  einige 
hundert  Meilen  transportiert.  Das  Resultat  war  ahnlich  wie  bei  den  Hunden,  nur 
nicht  so  ausgesprochen. 

X.  In  den  hyperplastischen  Schilddrusen  von  drei  jungen  und  einem  ausgewach- 
senen  Hund,  welche  mit  Wasser  und  Schlamm  aus  Fischteichen  und  Kratzmaterial  aus 
Fischtrogen  getrankt  wurden,  fanden  wir  kleinste  Nematoden  unmittelbar  unter  der 
Kapsel  oder  in  der  Substanz  der  Schilddriise.  Die  Wiirmer  waren  von  Anhaufungen 
von  Bindegewebe  eingeschlossen.  In  zwei  Fallen  wurden  nur  Uberreste  von  kleinen 
Nematoden  in  der  Schilddriisengegend  bei  Bachforellen  gefunden  mit  einem  Schild- 
driisenkrebs, der  sich  in  der  Riickbildung  befand.  Wenn  diese  Nematoden  eine  aetio- 
logische  Bedeutung  haben,  so  kann  es  nur  die  sein,  dass  sie  Trager  eines  ursachlichen 
Agens  sind. 

SCHLUSSFOLGERUNGEN. 

1 .  Die  Krankheit,  welche  unter  dem  Namen  Kiemen-Krankheit,  Schilddriisentumor, 
endemischer  Kropf  oder  Krebs  der  Schilddriise  bei  der  Lachs-Familie  bekannt  ist,  ist  eine 
bosartige  Neubildung. 

2.  Die  Krankheit  findet  sich  bei  Fischen,  die  unter  natiirlichen  Bedingungen  in 
bewohnten  Gebieten  leben. 

3.  In  Fisch-Ziichtereien  eingefiihrt   wird  sie  endemisch   und   bricht   zuweilen  in 
Epidemien  aus. 

4.  -Normale  Fische  der  Wildnis  entnommen  konnen  an  der  Affektion  erkranken, 
wenn  sie  in  Fisch-Anstalten  gebracht  werden,  in  welchen  dieselbe  endemisch  ist 

5.  Die  Fiitterung  mit  ungekochtem  Proteid  Material  vom  Tier  begiinstigt,  die  mit 
gekochtem  verzogert  den  Ausbruch  der  Krankheit.     Fiitterung  allein  ist  nicht  eine  wirk- 
same  Ursache.     Es  muss  dazu  kommen  ein  anderes  Agens,  das  wahrscheinlich  durch 
Wasser  oder  durch  Nahrung  oder  durch  beides  iibermittelt  wird. 

6.  Durch    Ausschaben    der    Innenflache     holzerner    wasserdurchtrankter    Fisch- 
Bottiche,  in  welchen  die  Krankheit  endemisch  ist,  erhalt  man  ein  Agens,  welches  nach 
der  Wirkung  auf  die  Saugetier-Schilddriise  durch  Vermittlung  von  Trinkwasser  zu 
urteilen  ohne  Zweifel  die  Ursache  der  Erkrankung  der  Fische  ist,  welche  in  diesen 
Behaltern  gehalten  werden. 

7.  Durch  Kochen  wird  dasselbe  zerstort. 

8.  In  alien  Stadien  der  Erkrankung  werden  Fische  giinstig  beeinflusst,  wenn  man 
dem  Wasser  in  gewisser  Verdiinnung  Quecksilber,  Arsen  oder  Jod  zusetzt. 


512  BULLETIN   OF  THE  BUREAU  OF  FISHERIES. 

9.  Die  Wirkung  des  Quecksilbers,  Arsens  und  Jods  auf  Schilddriisenkrebs  beim 
Fisch   und   die   daraufhin   vorgenommenen  erfolgreichen  Versuche   mit   Metallen  an 
Saugetieren  sind  wahrscheinlich  der  Ausdruck  einer  Heilwirkung  dieser  Elemente  beim 
Krebs. 

10.  Gewisse  Arten  der  Salmoniden  haben  beinahe  eine  vollige  natiirliche  Wider- 
standsfahigkeit  gegen  die  Erkrankung. 

1 1 .  Manche  Fische  von  empfanglichen  Arten  zeigen  einen  hohen  Grad  vom  Immu- 
nitat  gegen  die  Krankheit. 

12.  Spontanheilung  koramt  in  einer  betrachtlichen  Anzahl  von  Individuen  vor. 

13.  Ubertragung  aus  Teichen  mit  endemischer  Erkrankung  in  natiirliche  Umgebtmg 
oder  Ubergang  zu  mehr  natiirlicher  Nahrung  vermehrt  den  Prozentsatz  der  Spontan- 
heilungen. 

14.  Spontan-Heilung  scheint  einen  gewissen  Grad  von   Schutz  gegen  Riickfall  zu 
verleihen. 

15.  Der  Prozentsatz  der    Spontan-Heilungen    in    den    Friihstadien  der  Krankheit 
scheint  hoher  zu  sein  als  in  den  spateren  Stadien. 

1 6.  Das  Vorkommen  der  Krankheit  nimmt  mit  dem  Alter  des  Fisches  zu  wenigstens 
bis  zum  5ten  Jahr. 

17.  Schilddriisen-Vergrosserung  und  Veranderungen,  welche  nach  Verlauf  von  5 
Monaten  das   Bild   eines  diffusen  parenchymatosen  Strumas  darboten,   wurden   bei 
Saugetieren  erzeugt,  wenn  man  ihnen  Wasser  zu  trinken  gab  mit  ausgeschabtem  Material 
von  Fischbottichen,  in  welchen  die  Krankheit  endemisch  war.     Controll-Tiere,  welche 
dasselbe  Wasser  gekocht  erhielten,  zeigten  keinerlei  Veranderungen  an  der  Schilddriise. 
Dass  diese  Vergrosserungen  und  Veranderungen  an  Saugetier-Schilddriisen  die  ersten 
Stadien  derselben  Erkrankung  sind,  welche  bei  Fischen  vorkommen,  welche  die  obener- 
wahnten  Bottiche  bewohnt  haben,  ist  ein  Schluss,  welchen  nach  unserer  Uberzeugung 
weitere  Versuche  rechtfertigen  werden. 

1 8.  Die  Erkrankung  ist  zu  einem  hohen  Prozentsatz  in  alien  Forellen-Zuchtereien 
der  Vereinigten  Staaten  endemisch. 

19.  Das  Vorkommen  der  Krankheit  beim  wilden  Fisch,  ihre  Einfuhnmg  in  Fisch- 
Ziichtereien,  ihre  Localisation  in  gewissen  Bottichen  oder  Wasserlaufen,  die  Methode 
ihrer  Verbreitung,  ihre  Ubertragung  auf  Saugetiere,  die  Wirksamkeit  von  3  wohlbe- 
kannten  Germiciden  inorganischer  Natur  bei  der  Behandlung  der  Krankheit,  die  Zer- 
storung  des  Agens  durch  Kochen,  die  Erscheinungen  der  Spontan-Heilung  und  der 
Immunitat,  weisen  dringend  darauf  hin,  dass  das  ursachliche  Moment  der  Krankheit  ein 
lebender  Organismus  ist. 

20.  Es  ist  bisher  kein  Nachweis  geliefert,  dass  die  Krankheit  von  einem  Individuum 
auf  das  andere  iibertragen  wird. 

21.  In  einer  Reihe  von  Entwicklungs-Phasen  ist  die  Krankheit  identisch  mit  ende- 
mischem  Kropf.     Da  sich  eine  scharfe  Grenze  zwischen  sogenanntem  endemischem 
Kropf  und  dem  was  wir  als  Krebs  der  Schilddriise  auffassen  und  bewiesen  zu  haben 
glauben,  nicht  ziehen  lasst,  so  behaupten  wir,  dass  endemischer  Kropf  und  Schilddriisen- 
Krebs  bei  den  Salmoniden  ein  und  dieselbe  Krankheit  ist. 


CARCINOMA   OF  THE  THYROID   IN   SALMONOID   FISHES. 

RESUME. 

I/investigation,  dont  les  pages  suivantes  sont  un  compte-rendu,  du  carcinome  de 
la  glande  thyroi'dienne  chez  les  poissons  a  e"te  entreprise  par  le  directeur  du  Gratwick 
Laboratory  dans  le  cours  des  recherches  du  laboratoire  sur  la  nature  du  cancer  chez 
Phomme.  Le  President  des  Ktats-Unis  ayant  eu  son  attention  appel£e  sur  ce  travail 
a  instruit  le  bureau  des  poissons  d'y  prater  son  concours,  de  sorte  que  les  ressources  des 
Etats-Unis  et  de  1'Etat  de  New  York,  represented  par  ce  bureau  et  le  Gratwick  Labora- 
tory, 6tant  re"unies,  il  en  a  resulte  une  investigation  plus  e"tendue  de  grand  inte'ret  et 
de  grande  importance  autant  pour  la  pisciculture  que  pour  les  recherches  sur  le  cancer. 

Bonnet,  en  1883,  de"crit  une  maladie  des  branchies  chez  la  truite,  laquelle  est  sans 
doute  identique  avec  le  sujet  de  ce  travail.  Cette  description  est  done  la  premiere 
publication  sur  ce  sujet,  quoique  la  nature  de  la  maladie  ne  fut  pas  alors  reconnue. 
Scott  en  1891  fut  le  premier  a  reconnaitre  la  maladie  comme  carcinomateuse  sans  toute- 
fois  reconnaitre  sa  relation  avec  la  glande  thyroide.  Son  origine  dans  la  glande  thyroide 
fut  avancde  en  premier  lieu  par  Plehn  en  1902,  elle  en  fit  le  diagnostic  de  Tad^no-car- 
cinome.  Pick  publia  en  1905  la  premiere  e"tude  un  peu  complete  sur  la  structure  de 
ces  tumeurs  et  insista  sur  leur  nature  cancereuse.  Gillruth  en  1902  le  de"crit  comme 
une  e"pitheliome  ayant  siege  dans  les  arcs  branchiaux  et  dit  qu'on  le  trouvait  dans  la 
plupart  des  £tablissements  de  pisciculture  de  la  Nouvelle-Zelande.  Gaylord  com- 
men^a  son  e"tude  de  la  maladie  en  1908  et  fit  un  rapport  dans  lequel  il  attira  1' attention 
sur  la  nature  infectieuse  de  la  cause.  Marine  et  Lenhart  comme  re"sultat  de  leurs  etudes 
commencees  en  1909  considerent  la  maladie  comme  e"tant  un  goitre  ende"mique  et  disent 
qu'ils  n'ont  pas  trouve"  de  sujets  dans  lesquels  ils  ont  trouve  aucun  sympt6me  de  cancer. 

La  maladie  est  grandement  r£pandue  a  t  ravers  les  Etats-Unis  et  existe  probable- 
ment  plus  ou  moins  partout  ou  I'elevage  artificiel  des  salmonid£es  est  continue"  plus 
loin  que  dans  leur  £tat  primitif. 

II.  Les  follicules  thyroidiens  chez  les  salmonide'es  ressemblent  a  ceux  des  mamma- 
liens,  mais  la  glande  n'est  pas  encapsulee  ni  si  limite'e  dans  sa  situation.     Chez  les  truites 
de  ruisseaux  sauvages  les  plus  grandes  collections  de  follicules  sont  a  peine  macroscopi- 
quement  visibles,  et  tout  le  tissu  thyroi'dien  est  place"  aux  alentours  de  1'aorte  ventrale 
du  cote"  dorsal  entre  les  premier  et  troisieme  arcs  branchiaux  et  ne  s'6tend  pas  laterale- 
ment  le  long  de  ces  arcs.     Leur  distribution  est  quelque  peu  moins  restreinte  que  ne 
1'indique  Gudernatsch.     On  trouve  souvent  des  depots  irr£guliers  sous  1'epithelium  de 
la  fosse  jugulaire,  mais  ils  sont  rares  autre  part.     Les  follicules  thyroi'diens  des  truites 
sauvages  sont  de  forme  re"guliere,  g£n£ralement  spheriques  ou  un   peu  allonge's,  dans 
les  conditions  types  et  normales  ils  sont  composes  d'e'pithe'lium  ge"ne"raletnent  aplati, 
mais  dans  aucun  cas  plus  haut  que  cuboi'de. 

III.  Une  simple  hyperplasie  de  la  thyroide  chez  la  truite  existant  dans  des  condi- 
tions sauvages  se  rencontre  assez  souvent.     Les  follicules  sont  augmented  en  nombre, 
leur  forme  est  plus  irreguliere,  la  substance  colloi'dale  est  diminuee,  1'epithe'lium  est 
pour  la  plupart  columnaire.     La  me" me  hyperplasie  existe  aussi  chez  la  truite  d'elevage 
et  ne  peut  etre  distinguee  des  premiers  developpements  du  carcinome  de  la  thyroide. 


514  BULLETIN   OF  THE   BUREAU   OF  FISHERIES. 

La  truite  de  mer  (Salmo  trutta)  dans  ses  premieres  annees  presente  aussi  quelquefois 
cette  simple  hyperplasie,  et  on  trouve  meme  quelques  adultes  avec  un  goitre  colloidal. 
La  gu£rison  spontanee  du  carcinome  chez  le  poisson  ne  resulte  pas  en  goitre  colloidal. 

IV.  On  trouve  generalement  comme  premiere  evidence  macroscopique  de  la  mala- 
die  un  foyer  d'hyperhemie  sur  le' plancher  de  la  bouche  (plancher  rouge).  Le  premier 
signe  visible  de  tumeur  se  voit  generalement  k  la  jonction  des  arcs  branchiaux.  Les 
tumeurs  peuvent  s'etendre  dans  differentes  directions,  soit  vers  le  plancher  de  la  bouche, 
soit  de  chaque  cdte  des  oui'es.  Des  tumeurs  independantes  peuvent  se  developper  dans 
la  fosse  jugulaire,  region  qui  contient  souvent  des  depots  de  tissu  thyroidien  normal. 
On  trouve  la  premiere  evidence  microscopique  de  la  maladie  dans  lesfollicules  individuels, 
generalement  dans  ceux  proches  d'un  grand  vaisseau.  Souvent  il  se  fait  qu'on  trouve 
a  ce  degr6  un  petit  groupe  de  follicules  alteres  entoures  par  des  follicules  normaux. 
L' epithelium  est  compose  de  hautes  cellules  cuboi'des  ou  en  colonnes,  le  protoplasme  et  les 
noyaux  prennent  un  coloris  profond.  La  substance  colloi'dale  est  diminuee  ou  manque 
completement,  les  vaisseaux  du  stroma  sont  hyperh£miques.  Ceci  est  suivi  par  un 
bourgeonnement  de  la  paroi  du  follicule,  formant  de  nouveaux  follicules  isoles,  de  type 
irr6gulier,  et  aussi  des  projections  papillaires  dans  les  follicules.  Comme  la  glande 
n'est  pas  encapsulee,  il  se  developpe  un  tissu  de  formation  nouvelle  entre  les  plans 
musculaires  et  qui  remplit  aussi  les  espaces  areolaires.  A  cette  epoque  on  trouve 
souvent  des  formes  karyokinetiques,  1' epithelium  est  en  colonnes  hautes;  le  meme 
follicules  contenant  souvent  plusieurs  couches  d' epithelium.  A  ce  moment  il  se  peut 
que  la  proliferation  soit  assez  developp6e  pour  donner  lieu  k  la  condition  reconnue 
comme  celle  du  plancher  rouge.  L'os,  le  cartilage  et  le  muscle,  tout  est  envahi.  La 
tumeur  ne  cherche  plus  le  chemin  de  moindre  resistance.  Dans  la  periode  ou  la  tumeur 
est  visible  les  variations  dans  le  caractere  de  la  proliferation  sont  remarquables.  Tous 
les  differents  types  peuvent  exister  dans  la  meme  tumeur.  On  peut  les  diviser  en 
alv^olaires,  tubulaires  et  solides,  ainsi  que  combinees  avec  les  types  papillaires  et  cysti- 
ques.  On  voit  souvent  de  petites  masses  ad£nomateuses  d'apparence  maligne  envahis- 
sant  et  infiltrant  le  tissu  thyro'idien  qui  apparait  moins  malin  aux  alentours.  II  arrive 
quelquefois  qu'on  trouve  des  ilots  de  tissu  thyroidien  normal  dans  les  espaces  et  cavites 
des  os,  tandis  que  le  tissu  environnant  a  ete  completement  remplace  par  le  thyroi'de 
carcinomateux.  Une  infiltration  vraie  de  1'os,  du  cartilage,  de  la  paroi  vasculaire,  du 
muscle  et  de  la  peau  a  ete  demontr6e.  Parfois  on  trouve  des  tumeurs  qui  presentent 
1'apparence  des  soi-disant  tumeurs  sarco-carcinomateuses  de  la  thyroi'de  chez  les  mammi- 
feres;  un  arriere-plan  de  cellules  en  fuseau  ressemblant  &  un  sarcome  avec,  caet  la,  des 
alveoles.  Les  croissances  sur  la  pointe  de  la  machoire  sont  soit  des  implantations,  soit 
des  m6tastases.  Ayant  trouve  une  tumeur  de  la  pointe  de  la  machoire  pareille  &  une  tu- 
meur thyroi'dienne  primaire,  nous  en  avons  fait  une  etude  speciale,  dont  il  resulte  que  cette 
formation  metastatique  a  probablement  lieu  &  un  point  bless6.  Dans  un  cas  de  tumeur 
trouvee  dans  la  paroi  intestinale  nous  avons  un  cas  certain  de  tumeur  metastatique, 
cette  tumeur  fut  trouvde  &  1'extremite  inferieure  des  intestins,  elle  infiltrait  d'un  vrai 
tissu  carcinomateux  thyroidien  le  tissu  "muscularis  mucosa"  de  la  paroi  intestinale. 
Ce  tissu  se  composait  de  grands  follicules  irrdguliers  doubles  d' epithelium  en  colonne, 


CARCINOMA   OF   THE   THYROID   IN   SALMONOID   FISHES.  515 

con  tenant  parfois  de  la  substance  colloi'de.  II  y  avait  des  parties  de  la  tumeur  qui  pr£- 
sentaient  1'apparence  des  tumeurs  primaires  les  moins  malignes.  Le  caractere  de  cette 
tumeur  et  la  region  ou  on  la  trouva  demontra  sans  aucun  doute  qu'elle  £tait  de  carac- 
tere me"tastatique.  Une  comparaison  des  differents  types  de  thyroi'de  carcinomateuse 
chez  les  salmonidees  nous  demontra  qu'on  peut  les  classer  approximativement  sous  les 
trois  groupes  proposes  par  Langhans  pour  le  carcinoma  de  la  thyroi'de  chez  les  mammi- 
feres,  c'est-a-dire  struma  proliferant,  struma  carcinomateux,  et  papillome  malin. 

V.  Trois  cas  de  la  maladie  ont  e"te  trouve"s  chez  les  poissons  sauvage  aux  Etats- 
Unis.     (i)  Chez  une  truite  de  ruisseau  qui  peut  avoir  ete  distribute  par  un  e'tablisse- 
ment  de  pisciculture;  (2)  chez  un  Laveret  (Coregonus)  qui  ne  peut  £tre  eleve1  ni  nourri 
artificiellement ;  (3)  chez  un  saumon  de  lac  (Salmo  sebago). 

VI.  La  maladie  a  ete  observee  chez  16  especes  ou  hybrides  des  salmonidees. 

La  formation  geologique  aux  sources  des  eaux  dans  lesquelles  on  trouve  la  maladie 
semble  n'avoir  rien  k  faire  avec  son  origine,  de  meme  que  le  contenu  dissous  dans  1'eau. 

La  maladie  est  ge'ne'ralement  endemique,  rarement  epidemique.  On  la  trouve 
dans  les  viviers  et  bassins,  quelle  que  soit  leur  construction,  ou  les  poissons  sont  gardes, 
eleve's  et  nourris  avec  la  nourriture  proteidienne  ordinaire  de  la  pisciculture,  c'est  & 
dire,  foie,  coeur,  poumons  et  autres  viandes  crues.  Elle  parait  avoir  une  tendance  a 
augmenter  en  descendant  un  cours  d'eau.  Les  hybrides  du  saumon  de  la  cote  du 
Pacifique  semblent  specialement  susceptibles  et  pr6sentent  un  grand  pourcentage  de 
cas.  Ouand  la  maladie  est  endemique  son  cours  est  lent  et  chronique,  avec  une  mor- 
talite"  difficile  a  determiner  a  cause  de  complications  avec  des  infections  secondaires  ou 
terminales  at  autres  causes  de  mort.  Le  nombre  des  tumerus  varie  e'norme'ment  et 
augmente  avec  1'age  du  poisson.  Des  tumeurs  visibles  macroscopiquement  n'ont  pas 
£t€  vues  dans  des  poissons  de  moins  de  5  mois.  Une  anemie  et  cachexie,  souvent  extreme, 
accompagne  generalement  la  maladie,  mais  cette  condition  peut  manquer  completement. 
L'immunite'  se  voit  d'une  maniere  remarquable,  non  seulement  parmi  les  especes,  comme 
chez  les  truites  de  mer  (Salmo  trutta) ,  mais  aussi  parmi  certaines  bandes  contenant  des 
especes  susceptibles.  Quand  des  poissons  affectes  sont  deplaces,  soit  dans  un  autre 
vivier  non  infect  e  ou  mis  dans  des  conditions  sauvages,  un  mouvement  retrograde  et 
meme  une  guerison  a  lieu  assez  souvent. 

VII.  Des  truites  de  ruisseau,  quoique  ayant  etc1  nourries  pendant  plusieurs  mois  de 
tumeurs  de  poisson  et  meme  de  cancer  humain,  n'ont  presente  aucune  evidence  de 
maladie  qu'on  ait  pu  attribuer  &  cette  nourriture.     De  m£me,  des  truites  susceptibles 
quoiqu'ayant  ete  gardees  dans  de  1'eau  stagnante  contenant  de  la  matiere  de  tumeur 
de  truite,  ou  avec  des  poissons  infectes  dans  de  1'eau  circulant  non  renouvelee,  ont, 
elles  aussi,  donne  un  re'sultat  n£gatif.     La  tumeur  de  poisson  n'a  pas  encore  e"te"  trans- 
plantee  avec  succes,  quoique  des  greffes  ont  un  peu  grandi  et  n'etaient  pas  encore  necro- 
tiques  au  bout  du  troisieme  mois.     L'extrait  de  la  tumeur  est  tres  toxique  quand  on 
1'injecte  dans  la  region  thyroidienne  ou  autre  part.     Des  truites  de  ruisseau  venues 
d'endroits  non  habitus  et  enfermees  dans  des  viviers  de  ciment  et  nourries  avec  du  coeur 
et  du  foie  crus  ont  developpe  la  maladie  de  maniere  &  ce  qu'elle  fut  visible  microscopi- 
quement  au  bout  de  la  premiere  annee  et  un  carcinome  visible  macroscopiquement 


51 6  BULLETIN   OF  THE  BUREAU   OF  FISHERIES. 

entre  la  premiere  et  deuxieme  ann6e.  La  cuisson  de  la  nourriture  retarde  la  marche 
de  la  maladie.  Une  retrogradation  spontanee  semble  avoir  lieu  dans  un  grand  pour- 
centage  des  poissons  ainsi  nourris  au  bout  de  la  deuxieme  anne"e.  Des  truites  semblables 
nourries  avec  du  poisson  de  mer,  avec  de  la  nourriture  vegetale  ou  avec  une  combinaison 
de  moules  et  d'asticots  vivants,  retiennent  leurs  thyroi'des  normaux. 

VIII.  Les  sels  de  n'importe  lequel  des  elements  suivants:  iode,  mercure  ou  arsenic 
dissous  dans  1'eau  habitue  par  les  poissons,  interrompt  le  progres  de  la  maladie  et  ramene 
1'e'pithe'lium  thyroidien  a  une  condition  pour  ainsi  dire  normale.     Le  resultat  se  produit 
d'une  maniere  visible  au  bout  de  quelques  jours.     Ce  traitement  agit  sur  les  tumeurs 
visibles  de  maniere  que  leur  grosseur  peut  £tre  vite  diminu6e.     L'iode  et  le  mercure 
agissent  meme  quand  ils  sont  dilues  dans  des  millions  de  parties  d'eau.     L'iode  est 
effectif  quand  on  1'introduit  dans  le  systeme  digestif  aussi  bien  que  dans  1'eau.     Des. 
r£sultats  negatifs  furent  obtenus  avec  1' administration  du  thymol  des  deux  manieres. 

IX.  L'administration,  &  des  chiens,  de  la  boue  et  de  1'eau  des  viviers  ou  le  carci- 
nome  £tait  endemique,  montra  d'une  maniere  suggestive  que  la  boue  et  1'eau  contenaient 
un  agent  capable  de  produire  des  changements  bien  marque's  dans  la  thyroi'de.     Des 
raclures  d'interieur  de  vieux  bassins  a  poisson  dans  lesquelles  le  carcinome  de  poisson  a 
6t6  continuellement  reproduit  donnerent  des  r6sultats  positifs.     Pendant  six  mois  on 
donna  &  boire  &  quatre  chiens  de  1'eau  dans  laquelle  ces  raclures  avaient  €t€  mac6r£es. 
Tous  deVelopperent  une  hyperplasie  thyroi'dienne  marque'e  et  trois  d'entre  eux  des 
thyroi'des  grossis.     Les  thyroi'des  de  trois  autres  animaux  de  controle  a  qui  on  donna 
la  meme  eau,  mais  bouillie,  resterent  de  grandeur  normale.     Deux  d'entre  eux  £taient 
normaux  comme  structure,  tandis  que  le  troisieme  montrait  quelques  traces  d'hyper- 
plasie  probablement  caus£es  par  une  experience  ante"rieure. 

Des  rats  qui  avaient  €t&  nourris  avec  la  boue  et  1'eau  prises  des  viviers  ou  il  y  avait 
le  carcinome  et  qui  avaient  £t£  transported  une  journ£e  entiere  en  chemin  de  fer,  don- 
nerent un  resultat  n£gatif.  Tandis  que  d'autres  auxquels  fut  donnde  de  1'eau  avec 
raclures  de  bassins  k  poisson  ^galement  transported,  produisirent  des  rdsultats  semblables 
a  ceux  trouves  chez  les  chiens,  mais  &  un  degr£  moins  marque. 

X.  Dans  les  thyroi'des  hyperplastiques  des  quatre  chiens  dont  trois  e"taient  jeunes, 
auxquels  fut  donnee  la  boue  et  1'eau  de  vivier  ou  de  1'eau  contenant  des  raclures  de 
bassins,  on  a  trouve  des  vers  n£matoi'des  miniscules  directement  sous  la  capsule  ou  dans 
la  substance  du  thyroi'de.     Les  vers  £taient  entoure's  de  tubercules  de  tissu  conjonctif. 
Dans  deux  cas  seulement  des  restes  de  vers  nematoi'des  furent  trouvds  dana  la  region 
thyroi'dienne  de  quelques  truites,  dans  ces  cas  le  carcinome  etait  en  etat  de  r£trograda- 
tion.     Si  ces  vers  ont  une  signification  etiologique,  ce  ne  peut  etre  que  simplement  comme 
porteurs  de  1'agent  causatif. 

CONCLUSIONS. 

1.  La  maladie  connue  sous  les  noms  de  maladie  des  branchies,  tumeur  thyroi'dienne, 
goitre  endemique  ou  carcinome  de  la  thyroi'de  chez  les  salmonidees,  est  une  tumeur 
maligne. 

2.  La  maladie  se  presente  chez  les  poissons  vivant  en  liberte  dans  des  regions 
peuple'es. 


CARCINOMA   OP  THE   THYROID   IN   SAUMONOID   FISHES.  517 

3.  Quand  elle  s'introduit  dans  un  £tablissement  de  pisciculture  elle  devient  ende- 
mique  et  meme  quelquefois  e"pidemique. 

4.  Des  poissons  normaux  pris  loin  des  habitations  peuvent  contracter  la  maladie 
quand  on  les  place  dans  un  vivier  ou  elle  est  endemique. 

5.  Le  nourrissage  avec  des  produits  animaux  proteidiens  non  cults  accelere  le 
developpement,  tandis  que  les  memes  produits  cuits  retardent  sa  production.     Mais  le 
nourrissage  seul  n'est  pas  une  cause  efficace.     II  faut  le  combiner  avec  un  agent  transmis 
probablement  par  la  nourriture  ou  1'eau,  ou  peut-etre  par  les  deux. 

6.  En  raclant  la  surface  interieure  des  bassins  en  bois  dans  lesquels  la  maladie  est 
endemique,  on  peut  acquerir  un  agent  qui,  par  son  action  sur  la  thyroide  des  mammif eres 
quand  on  1'administre  dans  1'eau  potable,  est  tres  probablement  la  cause  de  la  maladie 
chez  les  poissons  gardes  dans  ces  bassins. 

7.  On  peut  detruire  1'agent  en  le  bouillant. 

8.  L'etat  des  poissons,  dans  n'importe  quel  degre"  de  la  maladie,  est  ameliore  favo- 
rablement  par  1'addition  a  1'eau,  de  mercure,  d'iode,  ou  d'arsenic  en  quantite  n6cessaire. 

9.  L'effet  du  mercure,  de  1'arsenic  et  de  1'iode  sur  le  carcinome  de  la  thyroide  chez 
les  poissons,  et  subsequemment  les  resultats  positifs  de  cet  usage  de  metaux  dans  le 
cancer  des  mammiferes,  font  croire  &  une  relation  th£rapeutique  entre  les  metaux  et  le 
carcinome. 

10.  Certaines  especes  de  salmonidees  off  rent  une  resistance  naturelle  presque  com- 
plete a  la  maladie. 

1 1 .  Certains  groupes  de  poissons  d'especes  susceptibles  montrent  un  degr6  d'immu- 
nite"  tres  eleve  centre  la  maladie. 

12.  Une  guerison  spontanee  a  lieu  dans  un  pourcentage  considerable  de  sujets. 

13.  Quand  on  change  les  sujets  du  local  ou  la  maladie  est  endemique  a  des  condi- 
tions naturelles,  ou  quand  on  leur  donne  une  nourriture  plus  naturelle,  on  remarque 
egalement  une  augmentation  du  pourcentage  des  gue'risons  spontanees. 

14.  La  gu£rison  spontan£e  semble  accorder  un  certain  degr£  d'immunite'  centre  la 
r£cidive. 

15.  Le  pourcentage  des  guerisons  spontan^es  semble  etre  plus  grand  dans  les  pre- 
miers degr£s  de  la  maladie  que  plus  tard. 

1 6.  La  susceptibilite  a  la  maladie  semble  augmenter  avec  1'age  du  poisson  au  moins 
jusqu'k  1'age  de  cinq  ans. 

17.  Au  bout  de  cinq  mois  on  a  remarque  un  developpement  thyroide  et  autres 
changements  qui  presentent  un  tableau  type  de  goitre  parenchymateux  diffus  chez  les 
mammiferes  auxquels  on  a  donn6  a  boire  de  1'eau  dans  laquelle  avaient  etc  suspendues 
des  raclures  de  bassins  dans  lesquelles  la  maladie  e"tait  endemique.     Les  animaux 
employes  comme  contr61e  qui  recevaient  la  meme  eau  bouillie  n'ont  pas  developp£  de 
changements  thyroi'diens.     Que  ces  developpements  et  changements  sont  les  premiers 
degres  chez  les  mammiferes  de  la  meme  maladie  qui  a  lieu  chez  les  poissons  habitant  les 
bassins  d'ou  les  raclures  ont  ete  prises,  voilk  une  deduction  que  nous  croyons  que  des 
experiences  plus  etendues  justifieront. 


518  BULLETIN  OF  THE  BUREAU  OF  FISHERIES. 

1 8.  La  maladie  est  endemique  dans  un  grand  pourcentage  des  £tablissements  de 
pisciculture  aux  Etats-Unis. 

19.  Que  la  maladie  se  presente  chez  le  poisson  sauvage,  qu'on  peut  1'introduire  dans 
des  e'tablissements  de  pisciculture,  qu'elle  se  localise  dans  certains  bassins  ou  cours 
d'eau,  la  maniere  dont  elle  se  repand,  sa  transmission  aux  mammiferes,  le  bon  r£sultat 
obtenu  dans  le  traitement  de  la  maladie  avec  les  trois  germicides  inorganiques  bien 
connus,  la  destruction  de  1'agent  par  la  chaleur,  le  ph£nomene  de  la  gu6rison  spontanee 
et  de  rimmunit£,  tout  semble  indiquer  que  1'agent  provocateur  de  la  maladie  est  un 
organisme  vivant. 

20.  Jusqu'a  present  rien  n'indique  que  la  maladie  peut  etre  transmise  directement 
d'individu  a  individu. 

21.  Dans  beaucoup  de  ses  phases  la  maladie  est  identique  avec  le  goitre  endemique. 
Comme  il  ne  semble  pas  y  avoir  de  point  de  demarcation  entre  le  goitre  endemique  et  ce 
que  nous  croyons  avoir  demontre"  etre  un  cancer  de  la  thyroi'de,  il  nous  semble  que  nous 
pouvons  dire  que  le  goitre  endemique  et  le  carcinome  chez  les  salmonidees  sont  la  meme 
maladie. 


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1909.  The  structure,  distribution,  and  variation  of  the  thyroid  gland  in  fish.     Journal  of  the 

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1911,  p.  709,  21  text  fig.,  5  pi. 
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1911.  Spontaneous  tumors  in  mice.     4th  Scientific  Report  on  the  Investigations  of  the  Imperial 

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1888.  Report  at  the  Association  of  American  Physicians  by  Dr.  W.  H.  Welch  of  Dr.  Halsted's 

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CARCINOMA    OF   THE   THYROID    IN   SALMONOID    FISHES.  521 

HALSTED,  WILLIAM  S. — Continued. 

1896.  An  experimental  study  of  the  thyroid  gland  of  dogs,  with  especial  consideration  of  hyper- 
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8207° — 14 ii 


522  BULLETIN    OF  THE   BUREAU  OP   FISHERIES. 

MARINE,  DAVID,  AND  LENHART,  C.  H. 

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191  ra.  Further  observations  and  experiments  on  the  so-called  thyroid  carcinoma  of  the  brook  trout 
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191  ib.  Continued  observations  and  experiments  on  the  so-called  thyroid  carcinoma  of  brook  trout 
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July,  1911,  vol.  22,  no.  244,  p.  217. 
MARSH,  M.  C. 

1902.  Hemoglobin  estimations  and  blood  counts  in  fishes.     Washington  Medical  Annals,  vol.  i, 

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1910.  Thyroid  tumor  in  salmonoids.     Transactions  American  Fisheries  Society,  1910,  p.  377,  i  pi. 
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1886.  Schilddruse  und  Thymus  der  Teleostien.     Morphologisches  Jahrbuch,  bd.  n,  p.  129. 
MCCARRISON,  ROBERT. 

1906.  Observations  on  endemic  goitre  in  the  Chitral  and  Gilgit  valleys.  Medico-Chirurgical  Trans- 
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1909.  Further  researches  on  the  etiology  of  endemic  goitre.  Quarterly  Journal  of  Medicine,  vol.  2, 
no.  7,  p.  279. 

1911.  The  experimental  transmission  of  goitre  from  man  to  animals.     Proceedings  of  the  Royal 

Society,  ser.  B,  vol.  84,  1912,  p.  155. 
MCCLELLAND,  JOHN. 

1837.  Inquiry  into  the  nature  and  causes  of  goitre.  Dublin  Journal  of  Medical  Science,  vol. 
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MlCHAUD. 

1906.  Die  Histogenesis  der  Struma  nodosa.     Archiv  fur  pathologische  Anatomic,  bd.  186. 
MURRAY,  J.  A. 

1908.  The  zoological  distribution  of  cancer.     Third  Scientific  Report  on  the  Investigations  of  the 

Imperial  Cancer  Research  Fund,  London,  p.  41. 
NEUBERG,  C.,  CASPAR:  W.,  UND  LOHE,  H. 

1912.  Weiteres  iieber  Heilversuche  an  geschwulstkranken  Tieren  mittels  tumoraffinen  Substanzen. 

Berliner  klinische  Wochenschrift,  bd.  49,  nr.  30,  p.  1405. 
PARKER,  T.  JEPFERY,  AND  HASWELL,  W.  A. 

1897.  A  text-book  of  zoology,  vol.  n. 
PICK,  L. 

1905.  Der  Schilddriisenkrebs  der  Salmoniden.  Aus  dem  Laboratorium  der  L.  und  Th.  Landau '- 
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I435"1 542- 
PICK,  L.,  UND  POLL,  H. 

1903.  Ueber  einige  bemerkenswerte  Tumorbildungen  aus  der  Tierpatho logic,  insbesondere  fiber 
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CARCINOMA   OF  THE  THYROID   IN   SALMONOID  FISHES.  523 

PI.BHN,  MARIANNE. 

1902.  BSsartiger  Kropf  (Adeno-Carcinom  der  Thyreoidea)  bei  Salmoniden.  Allgemeine  Fischerei- 
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1906.  Ueber  Geschwiilste  bei  Kaltblutern.     Zeitschrift  fur  Krebsforschung,  Berlin,  bd.  4,  p.  525. 

1909.  Fische  als  Uebertrager  der  Krebskrankheit.     Allgemeine  Fischerei-Zeitung,  i.  Juli,  1909, 

nr.  13,  p.  290-292. 

1910.  Ueber  Geschwiilste  bei  niederen  Wirbeltieren.     Travaux  de  la  deuxieme  Conference  Inter- 

nationale pour  1'Etude  du  Cancer,  Paris,  p.  221.     Discussion,  p.  787. 

1912.  Ueber  Geschwiilste  bei  Kaltblutern.  Wiener  klinischen  Wochenschrift,  xxv.  jahrg.,  nr.  19, 
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DE  QUERVAJN,  F. 

1904.  Die  akute,  nicht  eiterige  Thyreoiditis  und  die  Beteiligung  der  Schildriise  an  akuten  Intoxi- 
kationen  und  Infektionen  iiberhaupt.     Mitteilungen  aus  den  Grenzgebieten.     u.  sup.-bd. 
REGAUD,  C. 

1907.  Helrainthiase   extra-intestinal  et  neoplasmes   malins  chez   le   rat.     Comptes  rendus  des 

Seances  et  Memoires  de  la  Societe  de  Biologic,  t.  i,  p.  194. 
REPIN,  CH. 

1911.  Goitre  experimental.     Comptes  rendus  hebdomadaires  des  Seances  et  Memoires  de  la  Soci6t6 

de  Biologic,  t.  2,  1911,  p.  225-227. 
Rous,  PEYTON. 

1910.  A  sarcoma  of  the  fowl  transmissible  by  an  agent  separable  from  the  tumor  cells.     Journal 

of  Experimental  Medicine,  vol.  xm,  p.  397. 
Rous,  PEYTON,  MURPHY,  JAMES  B.,  AND  TYTLER,  W.  H. 

1912.  A  filterable  agent  the  cause  of  a  second  chicken  tumor,  an  osteochondrosarcoma.    Journal 

American  Medical  Association,  vol.  ux,  no.  20,  p.  1793. 
Rous,  PEYTON,  AND  LANGE,  LINDA. 

1913.  A  hitherto  undescribed  transplantable  tumor  of  the  fowl.     American  Association  of  Patholo- 

gists  and  Bacteriologists,  i3th  annual  meeting.     In  press,  Journal  of  Experimental  Medi- 
cine. 

SCHONE,  GEORG. 

1910.  Versuche  tiber  die  Beeinflussung  der  Wundheilung  und  des  Geschwulstwachstums  durch 
Stoffwechselstorungen  und  Vergiftungen.  Archiv  fur  klinische  Chirurgie,  bd.  93,  heft  2, 
p.  369. 

Scorr. 

1891.  Note  on  the  occurrence  of  cancer  in  fish.  Transactions  and  proceedings  of  the  New  Zealand 
Institute,  Wellington,  N.  Z.,  vol.  24  (issued  May,  1892),  p.  201,  i  plate. 

SEURAT,  L.  G. 

1912.  Sur  la  quatrieme  mue  des  nematodes  parasites.     Comptes  rendus  hebdomadaires  des  S6ance<5 

et  Memoires  de  la  Societe  de  Biologic,  t.  2,  1912,  p.  279-281. 
SIMON,  J. 

1844.  On  the  comparative  anatomy  of  the  thyroid  gland.     Philosophical  Transactions  of  the  Royal 

Society  of  London,  vol.  134,  p.  295. 
SIMPSON,  B.  T. 

1913.  Growth  centers  of  the  benign  blastomata  with  especial  reference  to  thyroid  and  prostatic 

adenomata.    Journal  of  Medical  Research,  vol.  xxvn,  no.  3,  p.  269. 
Si, YE,  MAUD. 

1913.  The  incidence  and  inheritability  of  cancer  in  mice.     Meeting  of  American  Association  for 

Cancer  Research,  May  5,  1913.     Zeitschrift  fur  Krebsforschung,  vol.  13,  p.  500,  1913. 
SMITH,  H.  M. 

1909.  Case  of  epidemic  carcinoma  of  thyroid  in  fishes.     Washington  Medical  Annals,  vol.  8,  no.  5, 

P-3I3- 
SZECSI,  STEPHAN. 

1912.  Ueber  die  Wirkung  von  Cholinsalzen  auf  das  Blut  und  iiber  die  Beeinflussung  von  Mause- 
tumoren  durch  kolloidale  Metalle.  Medizinische  Klinik,  nr.  28,  p.  1162. 


524  BULLETIN   OF   THE   BUREAU   OF   FISHERIES. 

THOMPSON,  F.  D. 

1911.  The  thyroid  and  parathyroid  glands  throughout  vertebrates,  with  observations  on  some  other 
closely  related  structures.     Philosophical  Transactions  of  the  Royal  Society  of  London, 
series  B,  vol.  201,  p.  91. 
TYZZER,  E.  E. 

1907.  A  study  of  heredity  in  relation  to  the  development  of  tumors  in  mice.    Journal  of  Medical 

Research,  vol.  17  (n.  s.,  vol.  12),  p.  199. 
VIRCHOW,  RUDOLP. 

1863.  Die  krankhaften  Geschwulste,  bd.  in.     496  p. 
WILMS,  M. 

1910.  Experimentelle  Erzeugung  und  Ursache  des  Kropfes.     Deutsche   medizinische  Wochen- 

schrift,  xxxvi.  jg.,  1910,  no.  13,  p.  604-606. 
W6WLER,  ANTON. 

1883.  Ueber  die  Entwicklung  und  den  Bau  des  Kropfes.     Archiv  fur  klinische  Chirurgie,  bd. 
xxix,  1883,  heft  3,  p.  754-366,  10  pi. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LVI. 


Fie;.  1. — From  Scott's  "Cancer  in  Fish."  1891.      Floor  of  mouth  of  Sa/mo  fontinal is,  showing    protrusion   of  tumor  in 
pharyngeal  floor. 


FIG.  2. — Drawing  from  microscopic  section  showing  acini  with  infiltration  of  surrounding  structure  of  individual 
cells.    After  Scott. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LVII. 


FIG.  3. — Rainbow  trout.      Redrawn    from   Gilruth's   colored   original,     1902.      Large  tumor  on  each  side  of  branchial 
junction.     Gill  fringe  distended  on  surface  of  lower  one. 


FIG.  4a. — Yearling  hybrid  salmon.     Massive  tumors  and  marked  emaciation.     I<ot  19SSa. 


P'IG.  4b. — Two  year  old  Sahno  sebaso,  extreme  emaciation.     I¥ot  1950. 


FIG.  4. — Salnio  foittinafis  2  years  old.      First  external  evidence  of  tumor  in   base  of  muscular  structure  of  isthmus, 
showing  marked  infiltrative  tendency  of  growth. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LVIII. 


II 


11 

FIG.  5. — Redrawn  from  Maurer,  1886.        Thyroid  of  n  trout  20  cm.  long;  shown  in  its  relation  to  the  branchial  arteries, 
seen  from  the  ventral  side. 

FIG.  6. — Redrawn  from  Maurer.  Median  section  to  show  distribution  of  thyroid  about  the  ventral  aorta  in  a  trout  2.5 
cm.  long. 

FIG.  7. — Redrawn  from  Maurer.     Cross  section  of  the  head  of  a  trout  embryo  of  30  days,  showing  earliest  evagination 
of  pharyngeal  epithelium  to  form  the  thyroid. 

FIG.  8. — Redrawn  from  Maurer.    Median  section  through  head  of  trout  embryo  of  35  days.     Primary  thyroid  vesicle 
(/)  still  attached  to  parent  epithelium  by  pedicle. 

FIG.  9. — Redrawn  from  Maurer.  Cross  section  of  a  trout  embryo  of  35  days.  Primary  thyroid  vesicle  (/)  separated  from 
parent  epithelium. 

FIG.  10. — Redrawn  from  Maurer.  Median  section  through  head  of  trout  embryo  of  41  days.  Compared  witli  figure  8,  it 
shows  that  the  elongated  primary  thyroid  vesicle  (/)  has  moved  backward  and  now  lies  ventral  to  the  aorta. 

FIG.  11. — Drawing  showing  gross  appearance  of  jugular  pit  from  below. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LIX. 


FIG.  12. — Salvelinus  fontinalis  in  sac  stage,  hatched  a  few  days;  showing:  relation  of  thyroid  follicles  to  invagination 
which  becomes  jugular  pit.      X86. 


Fi<;.  13. — Brook  trout  fry  showing  early  thyroid  follicles  containing  colloid  material.        XS6. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LX. 


FIG.  14. — Scotch  sea   trout.      Longitudinal  section  of    lower  jaw  above   showing   normal  thyroid  follicles;    below,  in 
the  right  hand  comer,  an  isolated  misplaced  thyroid  follicle  lying  adjacent  to  the  epithelium  of  the  pit. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXI. 


GILL  FILAMENTS  OF  4TH  ARCH 


HEAD  OF  KIDNEY 

ESOPHAGUS 


OPBRCULUM 


PREOPERCULUM 


CHEEK  MUSCLE  IN  SECTION 


ORAL  MEMBRANE 


4TH  BRANCHIAL  ARCH 


....3RD  BRANCHIAL  ARCH 


2ND  BRANCHIAL  ARCH 


ST  BRANCHIAL  ARCH 


HVOID  CORNi: 


FIG.  15. — Composite  picture  of  lateral  and  longitudinal  distribution  of  normal  thyroid  in  the  Salmon idsie,  with  vessels. 


1ST  COPULA  (CARTILAGE) 
1ST  BASI BRANCHIAL 

2ND  BASIBRANCHIAL 


ORAL  MEMBRANE 

TEETH  OF  TONGUE 


BASIHYAL 

TONGUE  c  RTIL'AGE 
H      OH'YAL 


MUSCLE 


2ND  COPULA  (CARTILAGE) 

4TH  BASIBRANCHIAL 
3RD  BASIBRANCHIAL 

3RD  COPULA  (CARTILAGE) 

: "  -|--.         VENOUS  SINUS 


;    . .{-MUSCLE 


ESOPHAGEAL  MUCOSA 


AND:AREOLAR  TISSUE 


HYPOHYAI,    SYMPHYSIS 
MUSCLE 


AURICLE 

BULBUS  AORTAE 
.VENTRICLE 


.'EPITHELIUM 

SUBMUCOSA 

SYMPHYSIS  OF  CLAVICLE— CORACOID  PAIRS 
VENTRAL  AORTA 
UROHYAL 


BRANCHIAL  SPACE 
FIG.  16. — longitudinal  and  dorso-ventrnl  distribution  of  thyroid  in  the  SalmoimUe. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXII. 


:,' 


B^§.-'''v       X-^v  "•;.        --W 

•KWL-:"1!  .**  —  *"  «liSiife*i%^  -'   W 


Fio.  17. — Wild  brook  trout  from  An  Sable  River;  8.2  cm.  lonsr;  cross  section  showing  distribution  of  normal  thyroid.     X86. 


-'. 


» 


r^-vC"V  •"• 
.^*  «:-  ?V-*U 


/^    v!  -OK-5^— ^     r^i 

£ 

=s?<^  *•    ,  '1'flF1  ""c?':-..  Gr-/ 


'*&*&&& 
•K.9^W 


k~  s*5?«*s**e'        af^^fe*  -? 

>%«c    •;£-•*  -  <-*8E--**$&' 

<%«^:  %^^'^^^SS 

l^y     ^f^ii  .,  ••-<'.? 

;5^->'         f  .'    ^ 


Fie.  18. — Algonquin  wild  brook  trout;  simple  hyperplasia;  high  cuboidal  epithelium  reduction  in  some  follicles  and 
absence  in  others  of  colloid.     Distinct  hyperaemia  about  follicles;  increased  amount  of  thyroid.        X86. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXIII. 


Fui.  19. — Domesticated  Scotch  sea  trout  fingrerling-;  normal  thyroid  structure.        X86. 


^V«   &l 

m  ; 


.  .  .  - 

"  j.V 


KIG.  20. — Dotnesticated  Scotch  sea  trout  fmgrerliiiK:  same  hatchery  as  above,  showing  simple   hyperplasia,   increased 
number  of  thyroid  follicles;  epithelium  high  cuboidal  and  low  columnar;  colloid  diminished.        X86. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXIV. 


£te 

.-    ' 


Kit;.  21. — Adult  domesticated  sea  trout,  normal  thyroid  structure.        X86. 


Kit;.  22. — Adult  domesticated   Scotch  sea  trout;  colloid  goiter.         X86. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXV. 


FIG.  25. — Brook  trout,  showing-  rectal  metastasis  of  thyroid  origin       (Anal  fin  pinned  back  to  show  tumor.) 


FIG.  24. — Brook     trout,    showing:    large 
round  tumor  springing'  from  the  jugular  pit. 


FIG.  23a. — A  view  of  normal  floor  of 
mouth  of  adult  brook  trout. 


FIG.  23 — Hyperemia  of  floor  of  mouth  of  adult  brook  trout, 
so-called  red  floor.  First  macroscopic  evidence  of  hyperplasia  or 
carcinoma  of  thyroid. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXVI. 


FIG.  26. — Brook  trout,  showing  massive  thyroid  tumor  in  the  mouth  cavity,  springing  froiit  the  floor  of  the  mouth. 


FIG.  27. — Two  year  old  brook  trout,  showing  massive  tumor  filling  the  entire  gill  space. 


FIG.  28. — Brook  trout,  showing  tumor  mass  at  the  tip  of  the  lower  jaw. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXVII. 


FIG.  29.— Brook  trout   showing  noclular  growths    in  FIG.  30.— Brook   trout  showing  numerous  tumor  vege- 

floor  of  mouth.  tations  in  floor  of  mouth. 


FIG.  31. — Section  of  floor  of  mouth  showing  thyroid  follicles  growing  in  epithelium  above  basal  membrane.         X70. 


i«*l«?"^L.r  "JOf*' L' f»&^      **&  : 


FIG.  32. — Section  from  floor  of  mouth  showing  histological  structure  of  papillary  growths   fouiul   in    floor  of  mouth 
illustrated  macroscopically  by  figure  3D.        X94. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXVII. 


FIG.  29. — Brook   trout    showing  nodular  growths    in  FIG.  30. — Brook   trout  showing  numerous  tumor  vege- 

floor  of  mouth.  tations  in  floor  of  mouth. 


FIG.  31. — .Section  of  floor  of  mouth  showing  thyroid  follicles  growing  in  epithelium  above  basal  membrane.         X70. 


'*  %      ri  •',  '    •*   "jfttffjT'^Tn'       J1  r*'  '  I '  "<4e!'t^>^*la»'  &&***'• " ' « 

:^ 


FIG.  32. — Section  from  floor  of  mouth  showing  histological  structure  of  papillary  growths   found   in    floor  of  mouth 


illustrated  macroscopically  by  figure  30.       X94. 


BUU,.  U.  S.  B.  F.  1912. 


PLATE  LXVIII. 


FIG.  33. — Infiltration  of  aortic  wall  by  alveolar  carcinoma  FIG.  35. — Same  section,  higher  power.     Tubular  struc- 

of  thyroid.  ture  with  mitoses. 


^r      f 


9       i>     *»      m         *«  J*      "     c^1-  a  *•  ?  *  i»  *  '* 

1  art^f^L       n 

#  ^* 


Vic,.  34. — Dniwinjr  showing  infiltration  of  surrounding  .structures  in  the  early  stage  of  carcinoma  of  thyroid. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXIX. 


FIG.  36. — High  power  section  of  the  early  stages  of  the  disease  showing  formation  of  new  follicles  by  budding  of  the 
alveoli  with  subsequent  splitting  off.     Note  karyokinetic  figures.        X200. 


FIG.  37. — Cross  section  of  the  lower  jaw  showing  growth  infiltrating  the  surrounding  structures. 


PLATE  LXX 


$Jrtt9&*S*£%fyi 
ra:-* 


mSKfsffSsssK^^^VwS^ 

FIG.  38. — Section  showing  the  mixed  type.     In  the  center  a  few  follicles  containing  colloid  with  background  of  spindle 
cells.     X280. 

am      <jm*i  'mn*y     fr .    ,•«       ._.~*     ,       -tifvi^mmm.    **    \.j~.-vr' *- 


. 
'  •  * 


'  • 


3fc 

*  N  '  m~    UI^BR 

js. ^  •.<•-.„ 

«*  o*        \S    •  '    •?*'  *••* 

3*          \WA  v.       ..i'.,»Wt 


FIG.  39. — Section  of  tumor  presenting  the  picture  of  proliferating  stntina  of  l,anghans.  showing  numerous  karyokin- 
etic  figures.        X600. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXXI. 


FIG.  40. — Section  of  lower  jaw  showing  nodular  development  in  various  portions  of  the  tumor  mass.        X10. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXXII. 


,      / 


Fir,.  41. — High  power  section  from  figure  39  of  a  nodule  showing  closely  packed  spindle  and  oval  cells  with  deeply 
staining,  nuclei,  with  here  and  there  an  attempt  at  alveolar  arrangement.        X94. 


•S     'fi 

&,.•>••' 


m^^M 


Fu;.  42. — High  power  section  from  figure  39  showing  a  small,   distinct   nodule  of  adenomatous  type  lying:  in    loose 
alveolar  structiire.        X94. 


Buix.  U.  S.  B.  F.  1912. 


PLATE  LXXIII. 


w&arasfe 

*iw<\ifjr  "^ ;%,  y •  i  StfSrf^B  •¥  i$ 
*fc*fc»»  iw^^&^aiS^UJ&V 


fe^S^S?^^^ 

•»>-• .  f  x'***>»»>5v:  »**«&,*?>>>•  i 

S^|4'!S^T%f^ 


ll  "S«^ 


X-~  tJL  ••'*  *«•  V>  ', 

&.^wte&Js4 
sS^aww^^w'l  ^ 
JKiw?-Y'i^W 

r^t^^w^ 

***<• 

e* 


pIG   43 — section  showing  intensive  nodular  growth  FIG.  44. — Section  showing  individual  follicles  of  more 

with    concentric    compression    of   the  surrounding   tumor         malignant    type    infiltrating    surrounding    tumor    tissue, 
tissue.        X40.  X130. 


i**  rrr1""  •  VHY  '^^*y«''<^*  -  &23J3& 

^^> 

»  •• •  •  « - 


FIG.  45. — Section  showing  encapsulated  nodule  of  papillar  type  lying  in  tumor  tissue  of  alveolar  type.         X94. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXXIV. 


r'lHj 


KIG.  46. — Section  of  floor  of  the  mouth  showing  tumor  cells  infiltrating  and  destroying  basal  membrane.     Splitting 
of  elastica.        X260. 


Km.  47. — Drawing  of  section  showing  normal  thyroid  tissue  isolated  in  a  bone  space  surrounded  by  tumor  tissue. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXXV. 


Fi«.48. — Section  showing  infiltration  and  destruction  of  cartilage.        X136. 


if    v  /i    *  r.  r1       i 

••  •  '/*&$$ 
•J$m&> 

^^  j$-  <&<*•''* 


FIG.  49. — Section  showing  involvement  and  destruction  of  bone.        Xl^ 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXXVI. 


pIG   50. — Section   showing  involvement  of  aortic  wall.     Tumor  alveoli  between  elastic  lamellae  of  media.        X260. 


FIG.  51. — Section  "showing-  infiltration  of  individual  muscle  fibres.     Cells  within  the  sarcolemma.        X500. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXXVII. 


1     V  -vT*.     Jt*  « -  r     J  »•*•  TA 

^^1^ 

iy&syQ 


Fio.52. — Primary  tumor  of  thyroid  region.    Alveolar  type.        X136. 


FIG.  53. — Section  of  metastasis  on  the  tip  of  the  jaw;   from  the  primary  tumor  shown  in  figure  52.        X136. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXXVIII. 


FIG.  54. — Photograph  of  metastatic  tumor  in  the  rectal  wall 
Normal  size. 


FIG.  55. — Microscopic  section  of  re 
mucosa  over  surface  of  tumor.        X86. 


sis  showing  attachment  to  the  intestinal  wa 


FIG.  56. — Section  of  rectal  metastasis  showing  tendency  to  the  formation  of  papillar  nodules.        X86. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXXIX 


^v 


J^^^Bre-^tty*  \\  J*:**44*  Jr- 

Hi(;,57. — High  power  section  of  rectal  metastasis  showing  infiltration  of  the  muscularis  mucosa.        X160. 


fe^^r^aii 


FIG.  58. — Section  showing  peculiar  type  of  fish   thyroid  tumor  which   may  be  compared  with  plate  2,  figure  6,  of 
Laiighans'  article  on  malignant  disease  in  the  human  thyroid.        X160. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXXX. 


FIG.  59. — Section  of  fish  thyroid  tumor  resembling  the  proliferating  struma  of  I,anghans  as  illustrated  in   plate  2, 
figure  12,  of  his  article.        X160. 


FIG.  60. — Section  of  proliferating  struma  in  man;  original  case  of  Langhans  to  be  compared  with  figure  58.      X160. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXXXI. 


FIG.  61. — Papillar  type  in  fish  thyroid  tumor  resembling  malignant  papillar  type  in  man,  as  illustrated  in  I<anghans' 
article,  plate  7,  figure  32.        X160. 


Fir,.  62. — Section   o 
figure  60.        X160. 


•„        T    %M«PE  *r    w  * 
original   case;   to  be  compared    with 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXXXII. 


FIG.  63. — Fish  thyroid  tumor   showing   tubular  type   resembling-  the  struma   of  Geisslar,   as   illustrated   in   plate   6, 
figure  27  of  L,anghans'  article.        X160. 


•fai  fefV^: 


FIG.  64. — Section  of  fish  thyroid  tumor.     Solid  type.     From  five-months-old  domesticated  brook  tro 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXXXIII. 


Kir;.  65. — Section  of  fish    tumor   closely   resembling    the   so-called    struma    nodosa,   with  "Wachstum  centrum"  of 
Aschoff.        X160. 


FIG.  66. — Section  of  struma  nodosa  from  a  human  thyroid  gland  ;  to  be  compared  with  figure  64.        X160. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXXXIV. 


FIG.  67. — Infiltrating  thyroid  tumors  in  the  gill  region  of  a  wild  white  fish    (Coregonus  c/ufaeiforniis.) 


:«S*  2» 


m          -$*> 

.1^-  T«A1 

8 ''**•  * ' ;<r «'  /''^  *^2i 
l^i^iiei.ySHw 


§ 


FIG.  68. — Microscopic  section  of  the  tumor  shown  in  figure  66.     Infiltration  of  wall  of  vein.     Cell  nests  in  lumen.       X136. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXXXV 


i<;.  69.—  Photograph  showing  tumor  in  a  wild  brook 


PIG.  70. — Low  power  photomicrograph  of  the  tumor  of 


trout  \SalveHnusfontinalis. ) 


figure  68.    Note  the  large  nodule  within  the  tumor  mass. 


^  ° 


N°te   the   Spindle   Cel1   character  of   the   tl"»or 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXXXVI. 


* 


KIG.  72. — Massive  thyroid  tumors  in   wild   Satnw  sebago  4  years  old,  caught  in  Sebago  I,ake.  Maine.      Largest  fish 
observed  with  tumors.     Natural  size. 


> 


FIG.  73. — Smallest  tumor  fish,  domesticated  brook  trout  5  months  old.     Natural  size. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  LXXXVII. 


FIG.  74. — Photograph  of  longitudinal  section  of  lower  jaw  of  landlocked  salmon;  illustrated  by  figure  72. 


t 


FIG.  75. — Section  showing  alveolar  type  of  tumor.     Wild  landlocked  salmon.     Illustrated  by  figure  71.        X160. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  XC. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  XCI. 


FIG.  84. — Section  of  wild  Wisconsin  brook  trout.  Raw  liver  feeding- 12  months.  Focal  development  carcinoma  of  the 
thyroid.  Small  group  of  follicles  with  columnar  epithelium.  Reduced  colloid.  Hyperaemia  about  follicles.  At  periphery 
normal  unaltered  thyroid  follicles.  XS6. 


FIG.  85. — Wild  Wisconsin  brook  trout.     Raw  heart  feeding  12  months.  Beginning  carcinoma  of  the  thyroid.        XS6. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  XCII. 


*r~ 

•• 

^. 

'      ' 


,. 


J-     " 


Fi«.  86.— Section  of  wild  Wisconsin  brook  trout  from  same  experiment.     Natural  food  12  months.     Normal  thyroid.       X86. 


A 


£P;/-J 

'Svatt 


,C^'''  • 

IIP' 

w 


- 


"•  JP  '  •  » '  - 

f;  X  \           »/j  - 

'  ^                                   '  '•  "'•     / 

'r*  •   t"             '  j&**—f     .   ' 

f    •  /           "T3fc-i.'. 


?Sr 


, 


iaiFi/ 

•  •-•<^rr 

:^>>:f       "<v;^- 

%%^/1    '  "K^-tO  r/%^-'-  :-    • 

>-:'i::\--*v- 


m 


*-, 


/ 


:^ 


s^Sl 


:.87. — Section  of  wild  Wisconsin  brook  trout.     Cooked  liver  feeding  12  months.     Normal  thyroid. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  XCIII. 


-  ..    ,   *-***• 

» 


Km.  88. — Wild  Wisconsin  brook  tront.     Fed  marine  fish  12  months.     Normal  thyroid.        X86. 


\         > 

.  jCfr  .-  :  <t-W-^ 


-^K  ^ 


""  >»• 


KiG.89. — Wild  Wisconsin  brook  trout.  Vegetable  food  12  months.     Normal  thyroid.        X86. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  XCIV. 


.1      V 
\  V!   <\ 


v^ 

FIG.  90. —  Low  power  section  at  median  line  through  thyroid  region  of  wild  Wisconsin  brook  trout,  showing  well- 
developed  carcinoma  of  the  thyroid  infiltrating  surrounding  structures,  bone  and  cartilage.  After  18  months  raw  liver 
feeding  at  Craig  Brook.  Experimental  induction  of  carcinoma  of  the  thyroid.  X13. 


PLATE  XCV. 


BULL.  U.  S.  B.  F.  1912. 


FIG.  91. — Section   of  thyroid   showing  spontaneous   recovery   from  carcinoma    of  the  thyroid.    Early  stage.    Wild 
Wisconsin  brook  trout.     Fish  No.  2099  A.        X86. 


FIG.  92. — Section  showing  spontaneous  recovery  from  experimentally  induced  carcinoma  of  the   thyroid   in  wild 
Wisconsin  brook  trout.     Fish  No.  2099  B.        X86. 


BULL.   U.  S.  B.  F.  1912 

'     .. 


PLATE  XCVI. 


FIG. 
and  heart 


93. — Section  thyroid  region  domesticated  yearling,  Cold  Spring  Harbor  hatchery,  kept  in  old  troughs.    Raw  liver 
feeding.      Well  developed  hyperplasia.        X86. 


ft*   ~^V   $f$          jJH&  ^~***~~ '     -~-~*  <-->^****^S — -^v  _  ^.,.       -a*^^*^^^^  *  '"  * 

mft^~  *•  "Virs*    -'  "          " 


FIG.  94. — Yearling  domesticated  brook  trout.  Cold  Spring  Harbor  hatchery.     Same  lot  of  fish  as  figure  93.     Kept  in 
water  of  Church  Spring.     Raw  liver  and  heart  feeding.     Normal   thyroid.        X86. 


BULL.   U.  S.  B.  F.  1912. 


PLATE  XCVII. 


FIG.  96. — Marked  hyperplasia  domesticated  brook  trout  used  as  control  for  figure  97.    Fish  1040,  table  ix.        X86. 


FIG.  97. — Fish  from  same  lot  treated  by  adding  in  continuous  concentration  potassium  iodide  in  the  water  1 : 5,000.000. 
Marked  regression  of  hyperplasia  at  the  end  of  13  days.    Fish  1039,  table  ix.        X86. 


PLATE  XCVIII. 


BULL.  U.  S.  B.  F.  1912. 


FIG.  98. — Marked  hyperplasia  domesticated  brook  trout  used  as  control  for  figure  99.    Fish  1070,  table  ix.        X86. 


FIG.  99. — 'Fish  from  same  lot  treated  by  addinsr  in  continuous  concentration  potassium  iodide  in  the  water  1  : 5, 000. 000. 
Marked  regression  of  hyperplasia  at  the  end  of  27  days.     Fish  1069,  table  ix.        X86, 


BULL.  U.  S.  B.  F.  1912. 


PLATE  XCIX. 


FIG    100— Hybrid  yearling  salmon.     I,arge  protruding  tumor  showing  marked  change  with  reversion  toward  normal 
type  as  the  result  of  treatment  with  iodine  added  to  the  water  by  continuous  flow  in  the  proportion  of  1  : 5,000,000 
days.    Great  visible  reduction  in  size  of  tumor.    Fish  1083.  table  ix.        X86. 


FIG.  101. — Section  through  tumor  retrograding  as  the  result  of  treatment  with  potassium  iodide  added  to  the  water 
by  continuous  flow  in  a  concentration  of  1  :  5.000,000,  at  the  end  of  31  days.     Large  area  showing  organization  by  connectiv 
tissue,  previous  hemorrhage  in  substance  of  tumor  induced   by  treatment.     Great  reduction  in  size  of  tumor.     I 
table  ix.        X136. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  C. 


*~ 


FIG.  102.— Control  for  figure  103.    Fish  1090.  table  xn.        XS6. 


FIG.  103. — Domesticated  brook  trout  from  the  same  lot  as  figure  102.  treated  with  bichloride  of  mercury  added  by 
continuous  flow  to  the  water  in  the  proportion  of  1  :  5.000.000  for  12  days.  Disappearance  of  hyperplasia.  Marked  reversion 
to  the  normal  type.  Fish  1089.  table  xn.  XS6. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  CI. 


- 
~t.. 

i 


FIG.  104. — Control  for  figure  105.     Fish  1085.  table  xn. 

^/^••1^P"»-/ 

Ijfc  1 

"f  YK-*        !  f 


WSL/ 

S***fis  <         / 

wwm       *<••*«•'•, 

vasr  r^5j 
U 

'«»,?Hte^    ' *• 

^  *»i )"    <> 

v  3^'    r    ^      '*%  »A  I  '   "~""^^*.-- 

i-w)(Mii  1OT 

TfD^'-Vi 

.c5vi^^-/ 


p 

L43^N! 


$ 


,  v  • 


V 


<ra  * 

JU-5?  o 


v.  \  V      W 

mKff 

,    m       W^-'|/ 

|^ 

&r, 

jiA.  / 


asSMT!/     ?  I 

!H$IJ/    / 


KIG.  105. — Domesticated   brook   trout   from   the  same   lot  as  fisrure  104.  treated  with  bichloride  of  mercury  added  by 
continuous  flow  to  the  water  in  the  proportion  of  1  : 5,000.000  for  14  days.     Disappearance  of  hyperplasia.     Marked 
to  the  normal  type.     Fish  1084.  table  xn.  X86. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  CII. 


v 


mgk^. 


FIG.  107. — Section  through  margin  of  large  tumor  retrograded  under  treatment  with  bichloride  of  mercury  1  :  5.000,000 
added  to  the  water  for  18  days.  Marked  atrophy  of  tumor  cells,  remnants  of  nests  of  cells  in  marginal  connective  tissue 
presenting  a  picture  similar  to  regression  of  carcinoma  in  mammals.  Fish  1065,  table  xn.  X86. 


BULL    U.  S.  B.  F.  1912. 


PLATE  CIII. 


,.-1(-    ion— Section  through  tumor  of  two-year  old  brook  trout  treated  with  bichloride  of  mercury  added  by  continuous 
flow   to  the  water  in  proportion  of  1:5.000.000.      Result  at  the  end  of  11  days.     Great  reduction  in  size  of  tumor.    Reversic 
of  tumor  tissue  to  the  normal  type.     Fish  1144.  table  xn.        X86. 


r*' 
\T*&V 


JSP* 

**&£ 


r.,  ..^,_-     ,,-«'-yVt,     ttptMilt'A,- 

i    •?«.:•.«*    ."iss/ssr^^Krs^ 


•Jf^^p*^^  v*s  .>-:•> 


p,G  i(j9 —Domesticated  brook  .rout.  Visible  tumor.  Marked  diminution  in  size  of  the  tumor  and  ma 
tumor  tissue  with  reversion  toward  normal,  as  the  result  of  treating  for  22  days  with  arsenic  trioxide  added 
flow  to  the  water.  Note  marked  change  in  epithelium.  Fish  2036.  table  xiv.  X86. 


rked  chanKe  in 
by  contm 


BULL.  U.  S.  B.  F.  1912. 


PLATE  CIV. 


~v, 

'-     * 


FIG.  110. — Section  of  thyroid  of  dog  21  used  as  control  for  dog  16,  figure  111.     Received  same   water  as   dog   16  but 


^^P^*^**'   ?*%SWr4S 


FIG.  111. — Section  of  thyroid  of  dog  16.  Marked  enlargement  of  the  thyroid,  well  developed  hyperplasia  as  the  result 
of  drinking  water  in  which  were  suspended  scrapings  from  fish  troughs  in  which  carcinoma  of  the  thyroid  in  fish  was 
prevalent.  X160. 


BULL.  U.  S.  B.  F.  1912. 


S 


^wSP  ^ 

! 


[J1C      CIIU      UI       I1VC      IlUJIllIlSi      1HJII1      UIlIlJ^-lllK       WtlLtl       i 

arcinoma  of  the  thyroid  was  prevalent.   The  same 


BULL.  U.  S.  B.  F.   1912. 


s  .r% 


Fu;.  114. — Section  of  thyroid  of  dog  20  used  as  control  for  dogs  22.  16  and  17.     Received  the  same  water  as  dogs  16,  17 
and  22,  but.  like  control  dog  21,  boiled  before  drinking.        X160. 


*^cm& 

*•******'?      M** 


Fu:  115. — -Dog  22.  Section  of  enlarged  thyroid.  Well  developed  hyperplasia  after  drinking  water  five  months  with 
suspended  scrapings  from  infected  fish  troughs.  The  same  experiment  and  result  as  dog  16.  figure  111.  and  dog  17, 
figure  112.  X160. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  CVII. 


Fie;.  116. — -Section  of  normal  thyroid  of  adult  female  dog.  mother  of  dogrs  15.  16,  17,  20,  21  and  22,  used  as  control  for 
dogr  18.  figure  117.     Received  same  water  but  boiled  before  drinking.        X160. 


fc         ^» 

>•.,  ^•..•'•J^|,Y 

' 


:;g 


Fit;.  117. — Section  of  markedly  enlarged  thyroid  of  adult  dog  18.     Result  after  five  months  drinking  water  in  which 
were  suspended  scrapings  from  fish  troughs  in  which  carcinoma  of  the  thyroid  in  trout  was  continually  developing.        X160. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  CVIII. 


Kit;.  118. — Section  near  periphery  of  enlarged  thyroid  of  dog  18.  The  process  is  less  intensive  than  near  the  center 
ns  illustrated  in  figure  117  and  119.  Columnar  epithelium,  marked  papillary  growths  into  distorted  alveoli.  Colloic 
absent.  X160. 


BULL.  U.  S.  B.  F.  1912. 


PLATE  CIX. 


V 

X»r*       Xfc., 


r     »•»     *?  *v  •         >  - 


FIG.  120.— Normal  thyroid  gland  of  rat  32  used  ns  control  for  rat  115.  figure  121.        X160. 


'^C 

_»,\»  r      |J?  rV    jIV 


Ab>*<.^!   ••T»T         »T*V.'J»TA      »••".*•  7. »«       IV*.    » 

f  90  days,  from  drinking  water  with   suspended  set 
it  conducted  in  Buffalo.        X160. 


•*•-*  ^-»*-^  •      f  A   ^v:  r      ».»      »••••• 

FIG.  121. — Hyperplasiaof  thyroid  in  rat  at  the  end  of 
nfected  fish  troughs  from  Craig  Brook,  Maine.     Experitneii 


BULL.  U.  S.  B.  F.  1912. 


PLATE  CX. 


•  V*  .  --'.      •-(  'v 


FIG.  122. — Section  of  dog's  thyroid  showing  tubercle  with  FIG.  123. — Section  showing  head  of  nematode  inclosed  in 

cross  section  of  nemntode  in  capsule.        X70.  tubercle.        X550. 


__3&d&« 

!  f  •        '  -CT  "'/F^t  •  .^»V    " 
v^'^Vr-   ^ 

£.«'.  f^ftaK\J 

••u  ..«•*•"     » -•>> 


•1 


FIG.  124. — Cross  section  of  nemntode  in  center  of  tubercle, 
in  dog's  thyroid.        X130. 


feg«x^4Jftf3PrvV  v<^  ^v 

.#>.  •-.*?•  ,>V  /  N^>  >    ./* 

^  -*J«3L^      AlHf       AA!.  Afc  "A;.-  ^ — •       . 


FIG.    125. — Healed     tubercle    showing    no    evidence    of 
nematode.        X130. 


L.,- 


^:>  vJ^Ma? 

ir''  ^^ilfe^ 

•f  '  M- ^1*  ^'^  ,"  ,^»  ^~  *_?*•*  lr         ^«      *«*  "*•  . * *-     * .  r       *\ 

:TT    »  •-«.»•.'>«•''   ^~    »*•  »*_**'*^      _^^^M^^^     *    •   , 


FIG.  126. — Section    of   tubercle    in  fish  showing  spaces 
evidently  occupied  by  nematode.        X240. 


FIG.  127. — Section     showing    healed    tubercle    in     fish. 

X130. 


CARCINOMA  OF  THE  THYROID  IN  THE  SALMONOID 

FISHES  :  :  :  By  Harvey  R.  Gaylord  and  Millard  C.  Marsh 

From    BULLETIN    OF  THE   BUREAU  OF  FISHERIES,  Volume    XXXII,    1912 


Document   No.    790     :     :     :     :     :     :     :     :     :     :     :     :     :      :      Issued  April  22,  1914 


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1914 


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